

Immersive Citizens - AI Overhaul is a plugin for "The Elder Scrolls V : Skyrim" whose purpose is to increase player in-game immersion by greatly improving Artificial Intelligence (AI) of friendly NPCs (citizens) in order to make them act and react like true humans in relation to their environment or to an aggressor. Specifically, this plugin deeply overhauls the AI used by NPC citizens when they are in a “standard state” and in a “combat state”. The “alert state” is left untouched. To explain, an NPC is in a “standard state” when he/she is unaware of an aggressor, a “combat state” when he/she has detected an aggressor, and an “alert state” when he/she is aware of an aggressor that cannot be located.
Immersive Citizens is officially featured by Bethesda Game Studios (source), therefore it has been tested and validated by BGS's quality assurance teams.

Combat State
This plugin greatly improves the root AI used by NPCs when they are in combat. Specifically, this mod adds a new "Survival Instinct" feature to the NPC AI.Survival Instinct
Survival Instinct is a feature which gives nearly all the friendly and unique NPCs of Skyrim the ability to properly evaluate danger from an aggressor and respond to it more realistically while under attack. In short, if an NPC is attacked and has no chance of winning against an aggressor, that NPC will run away from the aggressor and attempt to find a safe place (a hideout). The hideout is chosen randomly, and the number of hideouts NPCs can access depends on the size of the city in which they live. Hideouts can be an NPC's home, the local temple, the Jarl's stronghold, a mine, the local barrack, etc. This Video will show this feature in action and will explain how it works. A more complete explanation is available below.
How it works: Basic Rules
The basic rules are the following:- If an NPC is attacked by an aggressor who is 10 levels or more above them, the NPC will flee.
- If the attacked NPC's health is lower than a threshold percentage of that NPC's maximum health, that NPC will flee from the aggressor. At the moment, there are four percentage thresholds: 50, 40, 30 and 25. These thresholds are assigned according to the NPC's resistance to physical damages. For example, an NPC wearing a cloth outfit will flee once his health goes under 50%, while an NPC wearing full heavy armor and a shield will only flee once his health dips below 25%.
- the NPC's current level
- the aggressor's current level
- the NPC's current health
- the NPC's current resistance to physical damage (armor & armor spells)
- NPC(s) WILL NOT use Survival Instinct when they are currently enlisted as followers.
- Survival Instinct will only be used by friendly and unique NPCs.
- NPCs will use Survival Instinct against aggressors added by other plugins (Skyrim Immersive Creatures, Elemental Dragons, etc.).
- NPCs will use Survival Instinct against the player character (PC).
- Friendly NPCs added by other plugins (3DNPC, Inconsequential NPCs, etc) will also use Survival Instinct.
How it works: Advanced Rules
In addition to the rules cited above, special rules have been assigned to several NPCs (but not all) according to their personalities and their social rank. These rules have priority over the general rules when they conflict.
Civilian NPCs: The NPCs within the "Civilian" category never try to counter the aggressor when attacked. If they are attacked, they will flee and try to alert the guards. An NPC falls into the Civilian category when meeting ALL of the following requirements:
- The NPC's maximum level is capped at 10 or less
- The NPC is unarmored
- The NPC is unarmed (EXCEPTION: a dagger alone doesn't count as 'arms')
Strategist NPCs: The NPCs categorized as "Strategist" will tactically retreat for a few seconds once their health is reduced by half. During this move, they will keep their distance while healing themselves and refreshing their protective spells. Once finished, the Strategist NPC will go back into the fight. An NPC falls in this category when meeting ALL of the following requirements:
- The NPC is a member of the College of Winterhold
- The NPC has a mana pool higher than 63
Cautious NPCs: The NPCs categorized as "Cautious" will flee any aggressor who is more than 5 levels higher than them (instead of 10). Furthermore, these NPCs will flee when attacked by an "impressive" aggressor, even if the NPC is a higher level. Specifically, the following creatures are listed as being impressive: dragon, giant, giant spider and mammoth. An NPC is considered cautious when meeting ANY ONE of the following requirements:
- The NPC is a member of the Thieves Guild
- The NPC is a member of the Dark Brotherhood
- The NPC wears a cloth outfit (or is naked) and has no knowledge of protective spells
Fearless NPCs: The NPCs falling in the "Fearless" category fight to the death, regardless of their aggressor's attributes relative to their own. An NPC is considered fearless when meeting ANY ONE of the following requirements:
- The NPC is under the influence of a frenzy spell
- The NPC is dead (reanimated NPCs will fight until they turn to ash)
- The NPC is a member of the inner circle of the Companions
Khajiit Merchant NPCs: Unlike the other NPCs of Skyrim, Khajiit merchants will stay outside cities when they decide to flee. If they are near a city, they will hide inside a guard tower (Solitude, Riften), inside a city wall (Whiterun, Markarth, Windhelm), or inside a mine (Dawnstar). If they decide to flee while traveling between cities, they will flee in the direction of their destination.
Sleeping Agent NPCs: The vampires and Forsworn who hide among the NPCs of Skyrim will act as civilians unless they are attacked by the Dragonborn or if the time has come for them to show their true nature.
Combat Styles
At this time, defensive combat styles have been assigned ONLY to friendly and unique NPCs.Warrior NPCs
NPCs assigned to the "Warrior" class rely upon counter attacks to survive. For example, most Warrior NPCs will bash their aggressors (with high probability of success) when an aggressor tries to perform a power attack or a rapid succession of regular attacks against the Warrior NPC. Once the aggressor is staggered, the Warrior NPC will only perform one or two regular attacks while the aggressor doesn't have time to block.
Mages & Thieves/Archers
Mages and Archers will get out of melee range as soon as possible. Once out of melee range, they will attack behind a cover and they won't pursue their aggressor.Standard State
This plugin greatly improves the general behavior of friendly and unique NPCs while not in combat. It gives them new and realistic behaviors and makes them unpredictable (NPCs will act differently day after day). Note that some of the features described below haven't been implemented yet in some NPCs. More details are available in the "Modifications Overview" section.
The AI of each named NPC is customized according to the NPC's personal stories, social rank, personality, and relationships. To keep the description as short as possible, the AI of each NPC is not addressed specifically. Instead, the general concepts and the templates used are described as a starting point.
General Behaviors
The NPCs will now eat 2 or 3 times per day and sleep at least 6 hours per day. The sleep and meal times (while not sleeping) vary among NPCs within the following confines:- NPCs to go to bed: between 9pm and 3am
- NPCs wake up: between 5am and 9am
Specific Behaviors
According to their personal stories, social ranks, jobs, personalities, and relationships, some NPCs will regularly perform specific or unique activities. Here some examples of specific activities (most of them are associated with a job).
Hunter: The NPC will hunt game (deer, horker, hare, and fox) in the areas around the NPCs associated city/village. This will occur around 3 times per week during the morning hours. During the hunt, the NPC will check different areas to locate and hunt prey. If successful, the NPC will loot the corpse (pelt, meat, and alchemy components). The hunt process is reiterated until a specific amount of meat is looted, or when the hunt time frame expires. (Screenshots, Video)
Priest of Kynareth: The priests of Kynareth will pray to their goddess several times a day. They will also organize praying sessions with believers. When they are not praying, they will clean the temple and heal the wounded. Sometimes they will go to the market before it closes. (Screenshots)
Priest of Arkay: The priests of Arkay will pray several times per day in front of their altar. They will also bless the dead. Other duties consist of cleaning the temple and graveyard. They might also be found at the market before it closes.
Rambler: Some NPCs will stroll outside their city/village for various reasons:
- to enjoy the view of some landscapes
- to loot some alchemy components
- to travel to another village/city
Lover: NPCs involved in a romance will meet regularly in low-populated areas. If it is a forbidden romance, they will meet outside their city/village. (Screenshots)
Horse Rider: NPCs will use a horse if they have to travel long distances. Therefore, several horses have been added near the stables. (Screenshots)
Swordsman: NPCs using their swords to make their living (i.e., Warrior NPCs) will train themselves regularly in the art of fighting. Some will use their weapons against practice dummies (unless they use two-handed weapons) while others will have a sparring partner. (Screenshots)
Servant: Servants will perform all the tasks that is expected of them. They will cook 2 or 3 times a day and clean the house of their employer daily. Sometimes they will chop wood and carry firewood near their employer's fire pit. During the morning hours, they will go to the market to buy food.
Lumberjack: The lumberjack will use the sawmill daily. If there are several lumberjacks for one sawmill, there will be a turnover. They will also chop wood with an axe and deliver the firewood to the surrounding houses. Sometimes they will fix wooden walls.
Farmer: Farmers will work daily in the field. If a farmer works on a farm with multiple fields, the farmer will randomly choose from among them each day. If there are chickens, he will feed them daily. If there are cows, he will bring them water daily (some animations have been restored). If there is a grain mill, he will use it regularly, and sometimes he will tan an animal's hide or seal barrels containing food. (Screenshots)
Beggar: Beggars will spend most of their time at the market asking for charity. When the market is closed, you will find them drinking or sleeping in marginalized areas.
Additional Notes:
- Some of the templates described above have been combined and assigned to several NPCs. For example, if an NPC owns a farm and a sawmill, he will act both as a lumberjack and a farmer. Let’s take a more specific example with Uthgerd: she will act as a swordsman, a rambler, and a horse rider. She will also perform more general activities during her free time. In short, all NPCs will have a unique behavior and will act differently day after day.
- I assigned a protected flag to any NPCs which can make the decision to wander in the wild, so only the player can give them the final blow.
Free Time
To humanize the citizens of Skyrim, every day NPCs will perform one or several activities chosen randomly among a predefined list and customized to many NPCs. The bigger the city in which an NPC lives, the more activities that NPC can access. If an NPC has just one hour of free time, he can only undertake one activity, while if he has five hours free, he can undertake several activities. Here are some examples of activities:
- shopping at the market, a general goods store, or at a specialized store
- praying at the local temple
- drinking at the local tavern
- resting at home
- praying or standing in front of a grave
In short, each day NPCs will act differently (Album 1, Album 2, Album 3, Video).
Enhanced Social Interaction
Random Conversations: To improve the social interaction between NPCs, all vanilla NPC conversations present, but not implemented in the game, are now implemented by this mod. For each city/village, the number of unique conversations will be approximately doubled. (Video, Video 2, Video 3, Video 4)
Family: At least one time per day, the members of the same family will meet to have a meal unless tension exists between them or some of them live in different cities. (Screenshots)
NPC-Dependent Behavior: Some NPCs will change their behavior around other NPCs. This is especially true for children or NPCs engaged in group activities. Thus, if an NPC dies, the behavior of some other NPCs may change.
NPC Greetings: The probability for an NPC to engage in conversation with you has been drastically reduced except in cases where it is part of their job or disposition. In practice, only the merchants, beggars, and messengers will engage regularly in conversation with the player. So when you see Nazeem, you won’t feel the need to kill him or run away from him anymore. This feature also applies to all guards from any city/village and any official DLC.
Weather Influence
In Skyrim, the weather is sorted among 4 categories:- Pleasant
- Cloudy (foggy weathers also fall in this category)
- Rainy
- Snowy (sandstorms also fall in this category)
The citizens will adapt their activities according to these weather categories.
Take Shelter: If it is raining or snowing, NPCs will stop outdoor activities unless they can continue under a shelter, or if their work is critical. Otherwise, they will perform an activity taking place inside a building (a shop, temple, tavern, their home, etc.). The activity is chosen randomly from a predefined list. Each NPC will use a list customized according to his personal stories, social rank, personality, and relationships (Video).
Go Home: This feature has been developed for new NPCs added by mods like 3DNPC, Inconsequential NPCs, etc. During snowy or rainy weather, these NPCs will also stop their outdoor activities. However, contrary to the vanilla NPCs, they will just go back to their homes if they are outdoor. If they go back to home between 8am and 8pm, the NPCs will open their doors once inside their home (assuming they have one). However, if a NPC enters in its house while the player is already inside, NPC will ask the player to leave and will lock the door until the next day. If an NPC does not have a home, he/she will take shelter inside a tavern or in another public area. If there is no public area around, he/she will look for a fire camp. Note that NPCs will not use this feature if they are riding a horse or if they have one of the following jobs:
- Miner
- Lumberjack
- Blacksmith
- Ferryman
- Carrier
Additional Note: Some vanilla NPCs will use this feature temporally until their AI is fully overhauled. For more information, see "Modifications Overview" below.
Quest givers behavior
When an NPC gives the PC a quest, he'll continue to lead a normal life. For now, this applies only to the following quests:- The Golden Claw
- Trouble in Skyrim, Stealing Plans, Striking the Heart, and all the radiant quests given by the Companions
- The Blessings of Nature
- Missing in Action (Note: Once you accept to help Fralia, she will be in the Gray-Mane's house only between 5pm and 11pm.)
Other Behavior
Heimskr: Instead of annoying you from 5am to 8pm, Heimskr will only annoy you between 2pm and 6pm.Guards: For now, some guards will spend their money at “The Bannered Mare” at night.
Stupid dog / Good dog: A reset timer of 1 hour has been set for these sentences.
Opening time for services:
- Market: between 6am and 5pm (closed during snowy or rainy weather)
- The Drunken Huntsman: between 8am and midnight
- General goods vendor: between 8am and 8pm
- Apothecary: between 8am and 8pm
- Fletcher: between 8am and 8pm
- Horse dealer: between 6am and 6pm
- Blacksmith: between 6am and 6pm (if he works outdoors), otherwise between 8am and 8pm
Miscellaneous
Additional furnitures
The world of Skyrim lacks a lot of essential furnitures such as beds (there is just not enough beds for all citizens in Skyrim vanilla). In order to design interesting and realist AI, I've been compelled to add some shacks (3 in total) and some furnitures (example 1, example 2).
Bug fix
This plugin fixes several hundred of AI bugs not covered by the Unofficial patches. It fixes mainly 3 categories of bug:NPCs navigation
The navigation of NPCs has been greatly improved in Whiterun, Riverwood and Rorikstead. It means that this plugin dramatically reduces the number of NPCs teleporting themselves to reach their destination. It also prevents NPCs from getting stuck or making weird decisions in order to reach their destination. For example, thanks to the modifications done by this plugin, Camilla Valerius won't have problems anymore to reach the Riverwood's bridge when she shows you the path to Bleak Falls Barrow.
Scene & Conversation between NPCs
Concretely, It prevents some conversations between NPCs to be repeated continuously. It also fixes bugs preventing NPCs to have random conversations. Several broken scenes (missing NPCs, scenes not starting or starting at the wrong moment) have been also fixed. For now, these fixes only apply to the citizens of Whiterun, Falkreath, Riverwood, Rorikstead and Dark Water Crossing.
Random Encounters
It fixes several random encounters (a complete list and more details are available here), notably the patrols famed to get stuck somewhere on a road.
In game configuration menu
Immersive Citizens comes along with 2 in-game configuration menus allowing you to reboot, disable or update properly Immersive Citizens on your save. It also allows you to turn off some features that you may dislike. To have access to the MCM menu, SKSE 1.6.9+ and SkyUI 3.2+ are required, but they are NOT required to ensure the mod functionality, therefore they are optional. The other configuration menu is available through a racial power, it's a simpler version of the MCM menu that doesn't require SKSE and SkyUI. By default, all the features will be activated.

This plugin only affects the NPCs which are friendly and unique (named). Exception: The AI used by some guards in Whiterun has been improved. In total, Immersive Citizens improves the behavior of 601 NPCs.
Official NPCs
At this time, Immersive Citizens improves the AI used by NPCs living in the zones shown below and highlighted in green or in yellow.
The color code shows features implemented for each area.
Green: AI fully overhauled (all features have been implemented).
Light Green: The following features have been implemented: Survival Instinct, Go Home, Combat Style and General Behaviors.
Yellow: The following features have been implemented: Survival Instinct, Go Home, and Combat Style.
Grey: No modifications.
Towns: Dragon Bridge | Ivarstead | Karthwasten | Riverwood | Rorikstead | Shor’s Stone | Skaal Village
Settlements: Darkwater Crossing | Honningbrew Meadery | Kolskeggr Mine | Kynesgrove | Left Hand Mine | Nightgate Inn | Old Hroldan Inn | Soljund’s Sinkhole | Stonehills | Tel Mithryn | Whistling Mine
Strongholds: Dushnikh Yal | Largashbur | Mor Khazgur | Narzulbur
Farms and Mills: Anga’s Mill | Battle-Born Farm | Chillfurrow Farm | Half-Moon Mill | Heartwood Mill | Hlaalu Farm | Holly frost Farm | Katla’s Farm | Loreius Farm | Merryfair Farm | Mixwater Mill | Pelagia Farm | Salvius Farm | Sarethi Farm | Snow-Shod Farm | Solitude Sawmill
Faction: Jorrvaskr | College of Winterhold | Dark Brotherhood Sanctuary | Dawnguard Castle | Khajiit Caravan Camps | Thieves Guild HQ | Volkihar Castle
Aditionnal note: Immersive Citizens does not edit the AI used by Delphine, Esbern, adopted children and your spouse.
Unofficial NPCs
If you use one or several plugins adding friendly and unique NPCs, "Survival Instinct" and "Go Home" will be implemented in these NPCs. Note that, like "Wet & Cold" or "Run for Your Lives", "Immersive Citizens" will only handle a limited number of additional NPCs, here are the limitations:
- For the additional NPCs assigned to vanilla city/town/settlement, the limitation is 50 extra NPCs per vanilla city/town/settlement.
- For the additional NPCs assigned to new city/town/settlement or living in the wild, the limitation is 100 extra NPCs per hold (region).
- If you install a mod on an old save which adds extra NPCs while "Immersive Citizens" is already active in this save, don't forget to update "Immersive Citizens" through the configuration menu (more information in the section: Installation, Update & Load Order).

Incompatible Plugins
In theory, the lite version is compatible with everything. The compatibility level of the lite version is the same than the mod "Wet and Cold" and is better than than the mod "Run for your lives". The description page of the lite version is available here.
The only plugins which can disrupt or disable the AI added by "Immersive Citizens" are the ones modifying the layout of cities, villages, or interior rooms.
The plugins altering some dialogues, scenes or cells settings (image space and sound) can also conflict with Immersive Citizens, however, these conflicts will create minor incidents at best. As far as I know there is no popular mods for Skyrim SE altering dialogues or scenes which are incompatible with Immersive Citizens. Some mods are only compatible if you respect a specific load order, so please don't forget to check the load order section.
All the most popular plugins which are incompatible with Immersive Citizens are listed on this page. If you want to use plugins modifying the layout of cities, villages, or interior rooms, this page will also help you to pick plugins which are compatible with Immersive Citizens.
Interaction with quests and with plugin modifying NPCs AI
The AI temporarily implemented by vanilla quests have a higher priority than the AI implemented by "Immersive Citizens". Therefore, "Immersive Citizens" doesn't prevent the vanilla quests to work as intended. Popular mods improving NPC AI such as Wet & Cold and Holidays implement also AI with a higher priority than the one added by "Immersive Citizens". It's not a problem because AI from these mods are only used under very specific conditions. To summarize, either my AI has priority or my AI is overridden. Here is a concrete example involving the following mods: Wet & Cold, Holidays, Sleeping Innkeepers, My Home Is Your Home (MHIYH), Enhanced Skyrim Factions: The Companions Guild and my plugin. Whatever your load order, the game engine will use the modifications done on the AI by these plugins according to this order of priority (from top to bottom):
- Wet & Cold, conditions: The “Go Home” feature has been activated in the menu and it’s raining or snowing
- Holidays, condition: Active only during specific dates
- My Home Is Your Home, condition: Active only on followers selected through MHIYH's menu
- Immersive Citizens – AI Overhaul, condition: none
- Enhanced Skyrim Factions – The Companions Guild, condition: none
- Sleeping Innkeepers, condition: none
In practice, this means that the game engine will never use the AI modifications done by the mod “Enhanced Skyrim Factions: The Companions Guild”, because I have already overhauled the AI of all members of the Companions, but it will still use all the other features from this mod.
If you have “Wet & Cold” installed, the game engine will use my feature “weather influence” only if the “Go Home” feature from “Wet & Cold” is disabled.
Concerning "Run For Your Lives" & "When Vampires Attack", there is no interest in using them if you use Immersive Citizens, for the following reasons:
- Immersive Citizens supersedes these mods. Indeed, the feature "Survival Instinct" from Immersive Citizens works against any hostiles whatever the situation whereas "Run For Your Lives" & "When Vampires Attack" works only against some vampires and some dragons in very specific situations. Therefore, you won't get significant benefits in using them with Immersive Citizens, only downsides. For example, according to the author of "Run For Your Lives", sometimes "Run For Your Lives" can stuck forever NPCs inside their house, which is rather game breaking, more information about this issue can be found here. Due to the way immersive Citizens has been designed, NPCs can't get stuck forever in their homes which is a another major advantages of Immersive Citizens. This is why all the most popular mods compilations (STEP, Neovalen revisited, etc.) has definitely ditched "Run For Your Lives" & "When Vampires Attack" in favor of Immersive Citizens. Don't also forget that more mods in your load order also means potentially more bugs, more load order problems and more compatibility problems to deal with.
- If you're looking for an additional security, then any mod which adds a protected/essential flag to all NPCs (such as NPCs Protected Redux) will be much more efficient and complementary than "Run For Your Lives" & "When Vampires Attack". Indeed, although Immersive Citizens is very efficient to keep NPCs alive from agressors, sometimes, due to a game engine bug, some NPCs will die by falling either because they have been loaded too far away from the ground or because they have falled through a mesh. The only efficient way to protect NPCs against this kind of death is to use a mod which adds a protected/essential flag to all NPCs. It has been confirmed that this bug occurs without mods (source).
- Since the version 0.2.5, if you install on your save a mod adding extra NPCs while Immersive Citizens is already loaded in your save, then all you need to do to allow Immersive Citizens to affect these newly added NPCs is to update "Immersive Citizens" via a configuration menu available through a Power called "Citizens control" present in the magic section. Therefore, there is definitely no more interest to use "Run For Your Lives" & "When Vampires Attack" if you use Immersive Citizens.
- They may decrease your immersion. Indeed, NPCs will flee while there is no threat in sight, because these mods give to NPCs the ability to anticipate a dragon or a vampire attack, which is really something that ruin immersion in my opinion. This is why I ditched these mods and I started to develop my feature "Survival Instinct".
Concerning "Wet & Cold", unless you are only interested by the "Go Home" feature from "Wet & Cold", it is interesting to use it along Immersive Citizens. For your information, the “Go Home” feature from “Wet & Cold” is automatically disabled if you use Immersive Citizens. The author of "Wet & Cold" took this decision because the "Go Home" feature has been designed in a similar way than "Run For Your Lives" & "When Vampires Attack" and therefore it has the same bugs. Indeed, sometimes this feature can stuck forever NPCs inside their house.
Interaction with "Touring Carriages"
If you use my plugin along with "Touring Carriages", you will get fewer error messages from "Touring Carriages" because I fixed several navmesh bugs. When you use a carriage, all the NPCs (monsters included) will regard you as a friend. The carriage driver as well as the followers will also be regarded as a friend by all the NPCs. So when you use a carriage, the carriage driver will not flee if a hostile is prowling around. Once you leave the carriage this friendship ends, therefore the carriage driver can be attacked and if necessary, he can flee.
Interaction with plugins altering NPCs
Due to the way Immersive Citizens has been designed, Immersive Citizens is compatible with any plugins altering NPCs (inventory, outfit, appearance, faction, etc.).
Interaction with "Follower Overhauls" such as UFO, AFT & EFF
If you use UFO or EFF, your follower(s) won’t use “Survival Instinct”.
If you use AFT you have the possibility to turn on/off "Survival Instinct" for your follower(s). With AFT "Survival Instinct" is activated by default. To disable it or to reactivate it, talk to your follower(s), go in the tweak menu, then in the combat menu, choose a combat style to disable it or choose 'None' to reactivate it.
Interaction with "Combat Overhauls" such as Requiem, Skyre, Smilodon & Ultimate Combat
Due to the way Immersive Citizens has been designed, Immersive Citizens is compatible with any combat overhauls. Immersive Citizens is the first and for now the only one to modify the root AI used by NPCs when they are in combat, therefore, if you use a mod which edits combat styles, friendly and unique NPCs will use my combat styles whatever your load order. There is no bad or good synergy with those mods.
About the provided compatibility patches
Enhanced Lights and FX (only required if you use ELFXEnhancer.esp or ELFX - Hardcore.esp)
The compatibility patches provided for ELFXEnhancer.esp or for ELFX - Hardcore.esp combines the modifications done on some houses by both mods. Indeed, my plugin adds a lock list to some houses while ELFXEnhancer.esp or ELFX - Hardcore.esp changes the lighting template of houses, as well as their image spaces.
EnhancedLightsandFX.esp
Immersive Citizens - AI Overhaul.esp
ELFXEnhancer.esp / ELFX - Hardcore.esp
Immersive Citizens - ELFXEnhancer patch.esp / Immersive Citizens - ELFXHardcore patch.esp
Open Cities Skyrim
The plugin provided for OCS modifies my AIs in order to make them interact with the new towns created by OCS. Concretely, it transfers all my markers positioned in the world of Whiterun to the world of Tamriel. It also redesigns some of my AIs and solves some conflicts between navmeshes. Due to how difficult it is to make both mods work together, this patch may contain flaws. Note that this patch won't fix the quest bugs (if there are some) created by Open Cities Skyrim.
Recommended load order:
Open Cities Skyrim.esp
Immersive Citizens - AI Overhaul.esp
Immersive Citizens - OCS patch.esp
Enhanced Lighting for ENB (ELE)
The compatibility patches provided for ELE (version 0.9.5b) combines the modifications done on some houses by ELE and Immersive Citizens. Indeed, Immersive Citizens adds a lock list to some houses while ELE changes the lighting template of houses, as well as their image spaces.
Mandatory load order:
Immersive Citizens - AI Overhaul.esp
ELE_[any version]_Lite.esp
Immersive Citizens - ELE patch.esp
Realistic Room Rental Enhanced (version 1.8.3)
This plugin modifies my AIs in order to make them interact realistically with the new Inns. It also fixes several path-finding bugs and improves the AI used by the merchants from RRR. The aesthetic isn't modified in any way, just the part invisible to the player. Note that "Realistic Room Rental Enhanced" is not compatible with "Moonpath to Elsweyr" from muppetpuppet, and thus, this patch is not compatible with my patch for "Moonpath to Elsweyr". Note also that the improved version of "Moonpath to Elsweyr" implemented in "Legacy of the Dragonborn" from icecreamassassin is fully compatible with "Realistic Room Rental Enhanced" and with my patch for "Realistic Room Rental Enhanced".
Recommended load order:
RealisticRoomRental.esp
Immersive Citizens - AI Overhaul.esp
Immersive Citizens - RRR patch.esp
Moonpath to Elsweyr (version 9.5)
This plugin adapts the navigation mesh in Dead Man's Drink to the changes made by both mods. It also moves some furniture in order to facilitate the navigation of NPCs in Dead Man's Drink. Note that you don't need this patch if you use the improved version of "Moonpath to Elsweyr" implemented in "Legacy of the Dragonborn" from icecreamassassin. Also note that this patch is not compatible with my patch for Realistic Room Rental.
Recommended load order:
moonpath_questdata.esp
Immersive Citizens - AI Overhaul.esp
Immersive Citizens - MTE patch.esp
Unofficial compatibility patches
Here are listed the mods providing unofficial patches or addons which are functionals and which are safe to use whatever the version of Immersive Citizens.- Immersive Wenches. Not really a compatibility patch and thus totally optional. The plugin for Immersive Citizens from LordKoz will prevent the wenches added by Immersive Wenches to be affected by Immersive Citizens. So it's really a matter of personal preference to use it or not.
- Snazzy Furniture and Clutter Overhaul. This compatibility patch combines the changes made by both mods on some furnitures.
- Snazzy HD Furniture and Clutter. This compatibility patch combines the changes made by both mods on some furnitures.

Requirements:
Skyrim 1.9.32.0.8 (mandatory)
Dawnguard (mandatory)
Dragonborn (mandatory)
SKSE 1.6.9 or newer (optional)
SkyUI 3.2 or newer (optional)
Installation:
To install Immersive Citizens, it is recommended to use a file manager such as Nexus Mod Manager (recommended for newbie). If you use Nexus Mod Manager, click on the "Download NMM" button (located here) and follow the on-screen instructions. The custom installer will automatically select the required compatibility patches according to your plugin list. Then, ensure that the plugin(s) are activated.
For a manual install, download the file (the link can be found in the files tab of Immersive Citizens page), then extract in your Skyrim data directory (...\Steam\SteamApps\common\Skyrim\data) the content of one of the following folders:
- 10_Main_Full_Legendary_Version (if you want to install the full version requiring all the DLCs)
- 11_Main_Full_DG_DB_Version (if you want to install the full version requiring Dawnguard and Dragonborn)
- 12_Main_Lite_Version (if you want to install the lite version)
The other folders contain compatibility patches for the following mod: Enhanced Lighting for ENB (ELE ; there 4 different versions), 2 optional plugins from Enhanced Lights and FX (ELFXEnhancer.esp & ELFX - Hardcore.esp), Open Cities Skyrim, Moonpath to Elsweyr and Realistic Room Rental (Enhanced version). Install a compatibility patch only if you use the full version and if you use one of the mod or plugin listed above, otherwise you’ll get a crash before to reach the main menu.
To install a compatibility patch, extract the content of the folder containing the compatibility patch you need in your Skyrim data directory (...\Steam\SteamApps\common\Skyrim\data).
Then activate the plugin(s) in the Data Files menu.
Update/Reboot:
To update Immersive Citizens on your install, uninstall the old version of Immersive Citizens then install the new one.
To reboot or to completely update Immersive Citizens on your save, you can use the MCM menu or use the menu available through a racial power. Due to its simplicity, it is recommended to use the second one, especially if you want to update on a save with the version 0.2.4 or prior installed on it. But if you want to use the MCM menu, then open the MCM menu dedicated to Immersive Citizens, then in the general tab, untick then tick all the boxes which was ticked when you opened the menu, afterwards close the MCM menu.
Load order:
Due to the fact that Immersive Citizens alters some cell entries and navigation meshes, I recommend to position Immersive Citizens - AI Overhaul.esp near the bottom of the load order. If you use LOOT do not forget to update the online masterlist.
Make sure that your load order respects the following constraints:
- The main plugin (Immersive Citizens - AI Overhaul.esp) must be positioned above:
- DynDOLOD
- ELFXEnhancer (optional plugin from Enhanced Lights and FX ; ELFXEnhancer.esp)
- ELFX - Hardcore (optional plugin from Enhanced Lights and FX ; ELFX - Hardcore.esp)
- Enhanced Lighting for ENB (ELE_SSE.esp)
- More Tavern Idles (more idle markers.esp)
- Provincial Courier Service (Provincial Courier Service.esp)
- Realistic Water Two (RealisticWaterTwo.esp)
- Relationship dialogue overhaul (Relationship Dialogue Overhaul.esp)
- The provided compatibility patches
- The main plugin (Immersive Citizens - AI Overhaul.esp) must be positioned below:
- any plugin which edits Breezehome, Honeyside, Vlindrel, Hall Hjerim or Proudspire Manor
- Alternate Start - Live Another Life
- Bridges of Skyrim (Bridges of Skyrim.esp)
- Breezehome by Elianora (Eli_Breezehome.esp)
- Civil War Repairs (Civil War Repairs.esp)
- Dovahkiin Hideout
- Enhanced Skyrim Factions - The Companions Guild (ESFCompanions.esp)
- Hidden Hideouts of Skyrim City Edition
- Interesting NPCs (3DNPC.esp)
- Rayeks End - Mini Hideout
- Requiem (Requiem.esp)
- Routa - Stormcloak and Warrior cabin (Eli_Routa.esp & Eli_Routa - Non-Stormcloak.esp)
- Skyfall Estate (SE) (SkyfallEstate.esp)
- Skyrim Bridges
- Thornrock
- Whiterun Complete
- Whiterun Mansion
Note: When I state that Immersive Citizens - AI Overhaul.esp must be positioned above Relationship Dialogue Overhaul.esp, it means this:
Skyrim.esm
Update.esm
Dawnguard.esm
Hearthfires.esm
Dragonborn.esm
Immersive Citizens - AI Overhaul.esp
Relationship Dialogue Overhaul.esp

Does your plugin disrupt primary/secondary quests?
No, the AI used by quests have priority over my modifications.
Does your AIs are scripted / script-intensives?
No, the AIs are not scripted. Immersive Citizens adds only 4 scripts. One of them runs only once (during around 1 second) and his purpose is to activate Immersive Citizens the first time that you load it in your game. Another one is used to ensure compatibility with weather mods and to update Immersive Citizens when you install a new version. The 2 last one allow to add in-game configuration menus and thus, they run only on player command. Before the version 0.2.5, the mod was script-free.
Does your plugin have a significant performance impact?
No, no significant performances impact (around 1%).
Can I expect a lot of bugs?
No, all the AI added by Immersive Citizens have been tested by myself. I didn't delegate this task to individuals unrelated to this project due to the fact that it would require that I publish and update regularly the 574 decision trees, which is a tremendous amount of work with no guarantee of results. Therefore, I took the decision to test all the decision trees by myself rather than to spend time publishing decision trees because this assures me guarantee results.
I don't understand why some town overhauls are incompatible?
The word incompatible is not really suited, but it's a popular keyword. "Not designed to work with my plugin" is much more appropriate. Indeed, in order to maximize their realisms, the AIs added by "Immersive Citizens" have been designed to specifically interact with vanilla towns.
Keep in mind that TES5Edit is not able to detect bad synergies between plugins, so for most of the mods tagged as being incompatible, you won't see direct incompatibilities by using TES5Edit. The only direct incompatibilities that you may detect with TES5Edit are between navmeshes, but due to the way whom TES5Edit displays the data stored in navmesh entries, it's not even possible to design functional compatibility patches with TES5Edit to solve these incompatibilities.
A town overhaul is incompatible because it meets one or several of the following conditions:
- the plugin moves static objects such as houses, bridges, market stalls, archery targets, counters, tables, or walls. Therefore, the placement of some (or all) of my invisible markers, "idle marker" and "furniture marker" are not relevant anymore. This will lead to NPCs who interact with thin-air, perform actions unrelated to their environment, or who permanently collide themselves against walls or other static objects. This gif should help you to understand.
- the plugin disables or deletes static objects or "idle marker" and "furniture marker" which are used as reference by some of my AI packages. An AI package using disabled or deleted reference becomes nonoperational, so this will lead to NPCs becoming inanimate for a long period of time. Some of my AI packages have also been designed to interact with specific static objects, if they are disabled, then these AI packages will be not relevant anymore, this will lead NPCs to perform actions unrelated to their environment.
- the plugin adds static objects such as houses, bridges, or walls at the same location(s) where I added additional markers or furnitures. This will lead to NPCs becoming inanimate for a long period of time or who permanently collide themselves against walls or other static objects.
- the plugin edits the same navigation meshes without forwarding my modifications and the modifications from USSEP. This will lead to NPCs becoming inanimate for a long period of time, NPCs will be also unable to navigate around the static objects added by Immersive Citizens. In some cases, NPCs will lose access to some city districts and to some houses.
- the plugin disrupts NPCs navigation. If an NPC is unable to go from a point A to a point B, then his AI will be mostly ineffective.
So, if you use Immersive Citizens with a plugin modifying the layout of cities, villages, or interior rooms and it is listed as being incompatible, regardless of your load order, you may notice only minor changes in NPCs behavior and you can have some serious bugs.
Also note that the town overhauls offering a lot of compatibility patches or optional plugins are extremely problematic, because some of those optional plugins or compatibility patches are not compatible with my main plugin or with my compatibility patches.
Do you plan to support mods modifying the layout of cities, villages, or interior rooms and which are tagged as being incompatible?
No, because with my current resources, it would mean the death of the project. In hindsight, it was a mistake to provide plugins modifying Immersive Citizens in order to make it work with incompatible mods such as Open Cities Skyrim while I'm still working on Immersive Citizens. Indeed, at each major update of Immersive Citizens, I have to remake the compatibility patches modifying my work, because the use of an outdated plugin which modifies my work can corrupt your save file or decrease the stability of your game. Due to this mistake, I've already lost a lot of time and I don't intend to repeat the same mistake. Therefore, I chose to try to improve the compatibility and the modularity of Immersive Citizens rather than spending time making compatibility patches. Since the initial release of Immersive Citizens, the compatibility of Immersive Citizens has increased and thus the number of compatibility patches has also diminished.
Is it easy to make compatibility patches for mods such as Holds or ETaC?
No, if it was easy I would already have done it. If you don't have the level to make a mod similar or better than Immersive Citizens, then you don't have the level to do functional compatibility patches for this kind of mods, due to the fact that it would require to perform massive and subjective modifications to Immersive Citizens, notably on AI packages. Keep also in mind that at each major update of Immersive Citizens, it would require to update or remake those compatibility patches because the use of an outdated plugin which modifies my work can corrupt your save file or decrease the stability of your game. Note that to support ETaC, it would also require to make several compatibility patches, due to the fact that there is conflicts between Immersive Citizens and the optional plugins from ETaC and because there is also conflicts between compatibility patches from both mods.
Why some mods editing navigation meshes such as "Breezehome by Elianora" are only compatible if you position them above 'Immersive Citizens - AI Overhaul.esp" in the load order?
To allow Immersive Citizens to override unnecessary modifications (if they are presents) done on vanilla navmeshes by these plugins. These unnecessary modifications have been created automatically by The Creation Kit (it's a bug). For now, these modifications are not recognised as ITM (More information about ITM here) by TES5Edit while they should be recognised as such. If you don't respect my recommandations about load order, then NPCs won't have access anymore to some city districts and thus they will stack in some areas and some quests will be impossible to complete. Immersive Citizens doesn't edit the navigation meshes used inside Breezehome, Honeyside, Vlindrel, Hall Hjerim or Proudspire Manor, therefore, it's perfectly fine to load them above 'Immersive Citizens - AI Overhaul.esp" in the load order.
There is a lot of examples on the forum about individuals who had problems because they didn't respect my recommendation about load order. So don't forget to check if your load order is correct.
Did you check all the plugins listed as being compatible or incompatible yourself?
Yes, I didn't delegate this task to individuals unrelated to this project due to the fact that the time requirement and technical requirements to accomplish the task are extremely high. To determine if Immersive Citizens works correctly with a plugin modifying the environment of the citizens, it requires knowing the 574 decision trees added by Immersive Citizens. To characterize these decision trees, it requires to analyze all my custom AI packages through the Creation Kit, and thus it requires expert knowledge in AI package design.
If you don't know what to expect from NPCs, then you won't know what to look at and where to look and in what conditions to perform tests (time of day, type of weather, day of week, NPC in combat state or not, specific quest running or completed, ect.) and thus you won't be able to perform reliable and efficient compatibility tests, because NPCs act differently day after day.
Therefore, it's highly probable that I'm the only one who knows how this plugin is supposed to work and thus, I have a huge advantage to be able to determine if a plugin modifying the environment of the citizens is compatible or not.
Immersive Citizens has evolved a lot since its release and it will continue to evolve. Due to this, it's highly recommended to use the information that I provide as a reference (the incompatibility list is regularly updated) and to check the compatibility section after any major update.
What issues can I have if I use a mod listed as being incompatible?
Here are the main issues you can have by using "Immersive Citizens" alongside a plugin that modifies the layout or placement of objects in cities, villages, or interior rooms:
- NPCs performing actions with thin-air
- NPCs unable to navigate within cities or within some districts (this will prevent you to complete some quests)
- NPCs unable to enter or to leave a house (this can also prevent the completion of some quests)
- NPCs unable to enter or to leave a city (this will prevent you to complete some quests)
- NPCs permanently colliding into walls or other static objects
- NPCs becoming inanimate for a long period of time
Do you plan to make a lite version for Skyrim SE?
Yes, but no ETA though. The original edition of the lite version is used by few individuals, therefore, it's not a priority.
Your plugin overrides a few modifications done by USSEP, is this intentional?
Yes. Immersive Citizens is fully compatible with USSEP.
I use a mod adding new houses for the citizens of Dark Water Crossing which are homeless, will they use their new house if I use your mod?
Yes, they will use their new houses, no compatibility patch required.
Do you plan to do a tutorial about AI package or Navigation mesh?
Unlikely, mainly for 3 reasons:
- It would take me at least 2 months of work at full time (assuming I work 14 hours per day everyday) to write all I know about AI package and navmesh. Moreover, as I have no teaching skills, there is no guarantee that you'll understand.
- This kind of work does not interest me, otherwise I would have already done it in order to build a team
- I already share with you the result of more than 6 500 hours of work, which is Immersive Citizens.
If I install Immersive Citizens, will I spend my time searching for NPC involved in a quest?
No, because once an NPC is involved in a quest, he will remain near or inside his home, however his behavior will remain realist.
Is it relevant to use the following mods with Immersive Citizens?
Guard Dialogue Overhaul: It depends. If you like to interact with the guards, yes. Otherwise, no.
Multiple Floors Sandboxing: No, I do not recommend to use plugins modifying the default value used for fSandboxCylinderTop & fSandboxCylinderBottom, because the vanilla AI as well as my AI have been designed to use the default value of fSandboxCylinderTop & fSandboxCylinderBottom. If you increase the values used for these settings, this will lead in some cases to NPCs becoming inanimate during a long time and sometimes the game engine will fail to load some NPCs. Indeed, if an NPC uses a "sandbox" procedure, he will try to use any furniture in the sandbox area, even if the furniture is located in an inaccessible area (a locked room for example or an area not covered by navigation meshes). When an NPC tries to use a furniture located in an inaccessible area, he becomes inanimate, because he is waiting for an answer from path-finding algorithm, answer which will never come.
No NPC greeting: The more my plugin will be updated, the less it will be interesting to keep "No NPC greeting".
Sleeping Innkeepers: No.
Do you plan to fully overhaul the AI used by all NPCs which are friendly and unique (named)?
Yes, but I cannot give any ETA mainly because I am working alone on this project and because this project is the result of research work.
Is there a way to prevent extra citizen from being affected by your mod?
Yes, I created a faction for that purpose: NPCO_ExclusionFaction.
How long will a hostile stay in front of a citizen's door?
Assuming you do not leave the area, this is determined by the following game setting: fCombatDetectionLostTimeLimit. This game setting has been set to 300 which is 5 minutes. By modifying this value, you can get results which are completely different. For example, with a value of 60, you will have citizens fleeing around you permanently during your fights. This will add a lot of chaos. Some will like it, some will not.
How long will a citizen remain in a combat state once he reached a hideout?
A citizen will not be in combat state anymore if you kill his foe or if X minutes have past where X is equal to the value set for fCombatDetectionLostTimeLimit.
Once a citizen is no longer in a combat state, how long it takes for him to leave his hideout?
With the default time scale, it takes him between 1 & 120 seconds. If you use a timescale of 10, it will takes between 2 & 240 seconds.
What time scale is safe to use?
The AI has been designed to use the default time scale (20). It will work with any values between 0 and 20 (I don't see the point to increase the value unless to perform tests); however, I do not recommend to go under 10 because beyond that there are boring downsides. For example, if you use a value of 10, the time between the dragon attacks is increased by 2, the conversations between the citizens will need twice the time to reset, the citizens will need twice the time to leave their house after an attack, etc. Moreover, a lot of quests or mods (such as "Holiday" from Isoku) use the in-game clock and may stop working as intended if you decrease the time scale too much, so choose wisely.

This section covers all the issues which can be caused by my plugin if you do not use it correctly, it also covers issues present in Skyrim vanilla. If you do not find the issue you have in this section, it means that it is most likely not caused by my mod.
Please remenber that:
- This plugin does not edit the AI used by Delphine, Esbern, adopted children and your spouse.
- This plugin does not edit the detection mechanism.
- Some vanilla AI issues fix themselves when you reboot Skyrim.
- The "Merge Plugins" made by Matortheeternal is not able to merge correctly Immersive Citizens with other plugins. This is also true for most of the provided compatability patches
- Due to the way TES5Edit displays the data stored in some entries (navmesh entry for example), it is currently not possible to design a functional compatibility patch for town overhauls or interior overhauls by using TES5Edit.
- Immersive Citizens comes along with an in-game configuration menu allowing you to disable Immersive Citizens. This configuration menu is available through a racial power.
You might also require an adaptation time if you are used to find specific NPCs at specific places. For example, I have sometimes a user who complains that the innkeepers are never inside their inn. While in fact the innkeepers stay 22h on 24 inside their inn and when they go out, they stay near the entry and if you enter inside their inn they follow you inside. Just because innkeepers do not spend anymore their life leaning on a bar doesn't mean they are not inside their inn.
If a quest does not work as intended, it is very likely that the culprit is not Immersive Citizens because Immersive Citizens inject to NPCs an AI with a low priority. Most of time the culprit will be a mod injecting to NPCs an AI with a high priority or a mod belonging to one of the following category:
- Town Overhaul (Open Cities Skyrim included)
- Interior Overhaul
- Alternate Start
Game Engine Limitations
Fast Travel
The game engine is not able to update the position of NPCs during a fast travel. Therefore, if you fast travel directly to Whiterun, most of Whiterun's citizens will be late on their schedule.
For example, if you arrive during night time in a city via the fast travel, you will find in the streets a lot of NPCs walking toward their house in order to sleep. If you arrive during day time, you might find several shops closed.
To bypass this game engine limitation, I use the fast travel to reach a location near the city where I want to go. For example, instead to fast traveling to Whiterun, you should fast traveling to a watchtower near Whiterun. Because it's a game engine limitation, you will have the same problem with the vanilla AI.
Sleep/Wait
The game engine is not able to update the position of NPCs which are not moving when you use the sleep or wait menu. Therefore, if you sleep in an Inn between 10 pm and 8 am, when you wake up, all NPCs who was sitting when you started to sleep will be still there.
To bypass this game engine limitation, if you want to sleep in a public area, I recommend to start to sleep around midnight. You can also use the wait menu or sleep menu twice in a row. For example, you can sleep 7 hours, wait 2 seconds in order to allow the NPCs to stand up and to start moving. Then sleep again 1 hour.
NPC & Door
Sometimes, an NPC can be interrupted when he is opening a door (linked to a teleporter). If an NPC opening a door is interrupted, then he will stay during several seconds in front of the door he tried to open and therefore he will block the path leading to this door. As a result several NPCs may stack temporary in front of this door.
Sometimes, NPCs are no more able to navigate from a room to another room. To fix this issue, reboot Skyrim.
Miscellaneous
My game crashes (CTD) before I reach the main menu.
Either you do not meet the requirements (you do not have Dragonborn or Hearthfires or Dawnguard or use a pirated version of Skyrim), or you have installed a compatibility patch that you do not need, or your plugin load order is incorrect. The custom installer will automatically select the required compatibility patches according to your plugin list, if a option is not ticked, then you don't need it. If you get a crash before to reach the main menu, I recommend first to reinstall Immersive Citizens by following the recommandation from the installer.
If the problem persist, start TES5Edit, select all your plugins, and press OK. If a plugin is missing or if your load order is wrong, TES5Edit will give you a very explicit error message, as well as the name of the missing plugin or the name of the poorly sorted plugin.
I have a reproducible CTD in game when I try to update an old save.
If you have a CTD just after an update, reinstall the previous version and load your save, afterwards go in a nonpopulated area, disable Immersive Citizens by using the in-game configuration menu, then save. Once done, install the new version, load your save and reactivate Immersive Citizens by using the in-game configuration menu.
Most NPCs gather in some areas, then they stop to move and remain there for several hours or forever.
Most NPCs do not enter their home or do not leave their home.
NPCs are blocked by invisible walls.
This usually happens when you use mods which are not compatible with Immersive Citizens or when you stack plugins which modify the layout of the same place(s) or if you load order is incorrect. This can also be caused by a single plugin editing navigation meshes. Keep in mind that any plugin which edits navmeshes can potentially disrupts the navigation of NPCs and thus can disrupt the AI used by NPCs. Hopefully it is reversible as soon as you remove the culprit.
- First, make sure that you have respected my recommendations about the load order.
- Then, ensure that you are not using a plugin listed as being incompatible (see this page).
- If the issue persists, remove the plugin(s) which edits the architecture of the area in which the issue occurs.
Vilkas complains that I am using magic during the quest "Take Up Arms".
NPCs attack me during a brawl.
This happens when you use an enchanted weapon or a mod that adds a hidden cloak spell on the player. The purpose of a cloack spell is to add new abilities to nearby NPCs through a scripted magic effect. When the cloak spell hits surrounding NPCs, they will think that magic is used against them or that you are attacking them. Lots of scripted mods can cause this.
This mod should fix your problem.
My follower always runs away while I am fighting against a dragon.
You use a follower overhaul such as AFT. If you use AFT, you have the possibility to turn on/off "Survival Instinct" for your follower(s). With AFT, "Survival Instinct" is activated by default. To disable it or to reactivate it, talk to your follower(s), choose "let's talk about your abilities", then choose "change your combat style". Choose a combat style to disable "Survival Instinct" or choose 'None' to reactivate it.
I can't challenge Uthgerd in a hand to hand duel.
The dialogue to challenge Uthgerd will not show up if she is riding a horse. This has been done on purpose, because if you challenge her while she is riding, the brawl script will not work correctly.
I can't find Bjorlam.
Bjorlam is always around his carriage. At night, he sleeps in a tent near his carriage.
NPCs stay permanently inside their home.
Citizens don't react when I attack them.
Not related to Immersive Citizens. "Run for Your Lives" and "When Vampires Attack" are known to cause sometimes these bugs. More information about this issue can be found here.
A dialogue does not show up to start a brawl against an NPC or to start a secondary quest.
This kind of bug is usually caused by the use of an alternate start mod. Here are some examples of issues which have been copied from the description of "Alternate Start - Live Another Life" :
source: http://www.nexusmods.com/skyrim/mods/9557/?
- The Thane offer won't be available in every city right away if you use a property owner start. The quest interaction makes doing so impossible without sacrificing too much of the content to it.
- When choosing one of the two civil war starts, you are strongly advised to let the Jagged Crown scene play out. If you don't, the quest may fail to start and the entire civil war quest line will get jammed.
- Some quests in a major city you pick a start for may not be available until after you've left that city and returned later. This is normal. It's due to how "Change Location" events work in the game and there's nothing that can be done about it.
The introduction scene (The Forsworn Conspiracy) in Markarth doesn't start.
This is not related to Immersive Citizens. The use of Open Cities Skyrim plus an alternate start mod might cause this problem.
The citizens do not talk to other NPCs or have stopped taking to other NPCs.
Vanilla bug. In the areas fully overhauled, Immersive Citizens prevents this bug to happen with a good efficiently, but it is not perfect. Most of the time rebooting Skyrim is enough to fix this issue.
The bards still sing endlessly (in short they do not go to sleep) unless I ask them to stop singing.
This is how their AI has been designed by Bethesda's designers. I plan to fix this.
Vilkas and Kodlak are still statics.
This is how their AI have been designed by Bethesda when those two NPCs are involved in the quest "Take up Arms". That quest is automatically activated once a new game is started. You have 2 options: either you complete this quest by joining the Companions or you wait until I improve this terrible quest design.
After a fast travel, I found dead NPCs, however I don't know how they died.
It's very likely that they died by falling because they went through a mesh or because they have been loaded far away from the ground. It's a vanilla bug, presents since the release of the game. It has been confirmed by multiple individuals that this bug occurs without mods, click here to get an example. It seems that this bug occurs often when you use the fast travel system. Some NPCs seems to be specifically affected, such as eorlund (source: http://elderscrolls.wikia.com/wiki/Eorlund_Gray-Mane). The use of Open Cities Skyrim might also increase the frequency of this bug.
An NPC is late on his schedule.
Very likely because you have used the sleep menu or a the wait menu more than 1 hour or because you have done a fast travel. To fix this, open the wait menu and wait 1 hour.
Help ! I'm a newbie, I don't know how to install your mod.
If you are a beginner, first, I recommend you to watch this guide as well as this tutorial to learn how to clean your DLC.

TechAngel85, z929669, EssArrBee, DoubleYou & Greg for the decription's correction.
Perseid9 for his authorisation to edit "Inns and Taverns - Realistic Room Rental Enhanced".
The individuals who support my work through donations or endorsements.

Author: Arnaud d'Orchymont.
JawZ for the first FOMOD installer.
Kudix for the MCM logo.
Kopasov for the Russian translation of the MCM menu.
Bethesda for the Creation Kit & The Elder Scrolls V: Skyrim.
The SkyUI Team for SkyUI which allowed me to implement a configuration menu.
ALL RIGHTS RESERVED. This content of this Skyrim game modification may not be copied, modified, reproduced, re-uploaded, or sold in any form, whole or in part, without the express permission of the author. This includes, but is not limited to, all descriptions, files, quests, AI packages, and names.