Morrowind:NPCs

In Morrowind, a non-player character, or NPC, is a humanoid person other than your player character. Although the term is not used in the manual or in the game itself, it appears extensively behind the scenes, such as in console commands and the Construction Set. NPCs are distinct from Creatures. Any entity of one of the playable races is an NPC, even if they consistently attack instead of talking. An animal or magical being of any other species is a Creature, even if they seem to be intelligent (such as Dremora) or do not automatically attack.

For named NPCs see People.
For unnamed guards see Guards.

Living with NPCs
Your character can interact with  NPCs in numerous ways.

Conversation
By default, "activating" a living NPC will bring up the conversation window, as long as your character is not sneaking. Most NPCs are capable of talking to your character on a variety of topics. New topics can become available as you talk to them, or as you learn about the topics from other sources. An NPC's responses to a given topic are not always the same, however. Factors influencing conversation can include just about anything, but the most common are their disposition toward you, your Reputation, your race or class, your faction affiliations, or simply the luck of the draw.

It is possible for an NPC to gain or lose available topics by re-locating them to another area, even if it was one the game never canonically takes them to. The most common of these are topics associated with a specific settlement or region of Morrowind or Solstheim. For example, a Balmora-based NPC would lose topics relevant to their own city, but gain topics relevant to Gnisis or Pelagiad if they were respectively moved to those areas. While most non-hostile NPCs have at least a few unique lines of dialogue, there are also many generic, shared topics that can be assigned to any NPC that meets the given criteria. For instance, members of the Priest class know a great deal about the Divines, while anyone located on Solstheim will tell you about the various wildlife and enemies encountered there.

Almost anything an NPC says to you will be recorded in your journal, indexed by the topic that prompted it. The majority of quests begin through conversation with the right NPC. NPCs in Morrowind share a large amount of generic dialogue. Lines that are unique to a specific NPC are documented on that NPC's page.

Persuasion and Bribery
Aside from the conversation topics, the conversation window has some commands you can use to manipulate an NPC's disposition toward you. See the Disposition page for details.

Commerce
Some NPCs buy and sell certain types of items, sell ready-made spells, and/or charge for various services. These appear as extra commands in the conversation window. Prices are generally influenced by the NPC's disposition toward you; details can be found on the Commerce page.

Combat
Any NPC can potentially fight against you. Most will defend themselves if you attack, or respond to your criminal acts with violence. Some can be provoked into attacking you by taunts or by failed attempts at speechcraft. The particularly hostile (especially desperate criminals in their lairs) will attack you on sight. An NPC's behavior initiating or responding to an attack is influenced by three variables, Fight, Flee, and Alarm, which are described in more detail below.

Once an NPC is in combat, their behavior is governed by complex AI. They will typically use the best weapons, armor, and magic they possess, and use them in more or less the same ways your character does. The "best weapons and armor" rule has an amusing side effect, because an NPC will generally equip superior items as soon as they enter their inventory. This can result in merchants wearing some very outlandish outfits as you sell them your unneeded equipment. Unfortunately, it also means anything they put on is unavailable to buy back unless they are persuaded to put on something better before their inventory restocks.

The criminal implications of combat with NPCs are detailed on the Crime page.

Pickpocketing
Activating a living NPC while you are sneaking will attempt to pick their pockets. The criminal aspects of pickpocketing are described on the Crime page.

Looting
The corpse of a dead NPC, like the corpse of a dead Creature, is treated almost exactly the same as an inanimate container. It contains the NPC's full inventory, including anything they were wearing or wielding. The only difference is that as those items are removed, they will also be removed from the character's model, changing their appearance. Looted items are never considered stolen. Just as with creatures, you can catch diseases from accessing the corpses of certain NPCs.

Characteristics
There are a multitude of variables that define each NPC. Many of these, such as AI settings, are only of interest if you are designing mods, but some are more basic. NPCs have most of the same fundamental characteristics as your character&mdash;race, class, Attributes, and Skills&mdash;and they work very similarly. Every NPC also has a level, but unlike your character their level will never increase. Thus their Attributes and Skills will also never change, except through the effects of spells, enchantments, or potions. NPCs generally do not have birthsigns. NPCs also have some special values with broad effects on their tactical AI.

An NPC can have Attribute and Skill values that are fully customized, but most do not. Instead, there are formulae the game uses to auto-calculate the values from the NPC's race, gender, class, and level.

Class
An NPC can be of any of the twenty-one predefined PC classes. However, there are also many other classes not in that list that are predefined specifically for NPCs to use. They are described at NPC Classes.

Attributes

An NPC's Primary Attributes begin at level 1 with the exact same values they would have for a player character of the same race, gender, and class, if they had no birthsign. For higher levels, an amount is added to these starting values according to the following formulae:
Primary Attributes: + (Level -1) * (Sum of Modifiers)
Uses appropriate modifier for each skill governed by said Attribute - Major is 1.0, Minor is 0.5, and Miscellaneous is 0.2

An NPC's Secondary (derived) Attributes are calculated based on their current primary attributes as follows:
Health: ((Strength + Endurance) / 2) + ((Level - 1) * (Specialization Constant)
Specialization Constant is based on their class' specialization; 3 for Magic, 4 for Stealth, and 5 for Combat. And if Endurance is one of their class' favored attributes, their Specialization Constant gets a +1
Magicka: (Intelligence * 2)
Fatigue: (Strength + Willpower + Agility + Endurance)

Not all NPCs in-game follow these rules. There is an option called Auto-Calculate in the CS, and the above are the rules it uses when the option is turned on for an NPC.  Many NPCs instead have pre-set stats that do not change with those of the player.

Skills
An NPC's Skills also begin at level 1 with the exact same values they would have for a player character of the same race and class, with no birthsign. For higher levels, an amount is added to these starting values according to the following formula:
Skills: (Level - 1) × (Majority Multiplier + Specialization Multiplier)
The Majority Multiplier is 1.0 for a Major or Minor Skill, or 0.1 for a Miscellaneous Skill.
The Specialization Multiplier is 0.5 for a Skill in the same Specialization as the class, zero for other Skills.

Fight
Fight is a value between 0 and 100 that influences an NPC's (or creature's) tendency to initiate combat with you. A typical starting value for the average townsperson is 30. Fight is continually modified by a variety of factors, and the moment an NPC's fully-modified Fight reaches 100 or more, they will attack. Modifiers (only pertaining to NPCs except for the first two of these) include:
If you have attacked them, their fight increases by 100, thus practically guaranteeing that they will respond in kind.
Fight is modified by the distance between you. For NPCs, even violent types who hate you will not attack until you get into a certain range, while mild-mannered townsfolk aren't likely to attack even if you bump into them. For creatures, you'll note that different creatures have different ranges of hostility (e.g., small for Mudcrabs and Rats, fairly wide for most creatures, cell-wide for Slaughterfish).
If they are the victim of another, non-violent criminal act, their Fight is increased by five times the Bounty for larceny, pickpocketing, or trespassing.
If they are in earshot when a crime victim raises an alarm, their Fight will be increased by an amount that depends on their own Alarm value.
A Disposition above 50 will decrease Fight, while a Disposition below 50 will increase it.
Taunting, Bribery, and Intimidation all have the potential to increase Fight, although the exact amounts are not clear.
Resisting arrest will cause a Guard-class NPC's Fight to increase to 100.

The actual numbers involved at any given moment can be very difficult to determine, so the following general descriptions of base Fight values are provided for NPCs in the documentation of the Construction Set (with some incorrect information fixed), and augmented by looking at creature values in the CS:
100: Always attacks; also used for some creatures, e.g. Slaughterfish.
95: Will attack as PC gets fairly close (3000 units).
90: Will attack as PC gets close (2000 units) except at 100 Disposition; also used for the majority of hostile creatures.
85: Will attack as PC gets close (seemingly 1500 units).
83: Will attack as PC gets close (seemingly 1300 units); creatures only, e.g. Mudcrab.
80: Will attack as PC gets close if they dislike you enough (1000 units if under 25 Disposition, 200 units if under 45 Disposition, will not attack at 50 Disposition).
70 and under 70: Will never attack because of distance or disposition.
30: Will attack if they hate you and you commit a crime.
20: Will attack if they dislike you and you commit multiple crimes.
10: Will attack if they hate you and you commit multiple crimes against them.
0: Will only attack if attacked first; also used for some tame creatures like Pack Guars.

The distinction between and and or in the above is important.

Flee
Determines an NPC's (or creature's) tendency to flee from combat. Even though setting it to 100 on an NPC through the Console makes them more likely to flee, this might not always be true with some NPCs. This is because the AI on fleeing can be used on combat for the NPC, such as defensive spells and ranged combat, e.g. bow attacks. Note that NPCs in combat with you will almost always flee if you position yourself somewhere they cannot reach, e.g. via levitation.

Alarm
Indicates how strongly an NPC will respond to another person's call for help when they are the victim of a crime.

If you commit a crime and it is detected by an NPC, they will say something to you. This will notify other NPCs in the area.

When the other NPCs hear this, they will acknowledge it in different ways based on their alarm value. The higher the alarm value, the more the NPC is likely take action in response to the crime.

If an NPC has an alarm value of 100, you will always get a bounty if they hear of a crime.