- This article is about the creature. For the feat, see Summon Familiar.
A familiar is a small creature that is magically linked to its owner.
Familiars are summoned creatures and can be summoned or unsummoned freely unless they are killed. They do not try to engage in combat, and usually just follow behind the master. While summoned, they grant a bonus that is roughly the equivalent of a feat. As the master advances, so do the familiars. They gain more hit points, better saving throws, and so on. They also gain evasion and spell resistance. During character creation, they can be named. They are intended to essentially be small buff totems and cool looking pets.
Familiars can be directly controlled.
- Controlling familiars directly gives the player character a semi-permanent Immunity: Mind Spells effect, that will remain even after the familiar is unpossessed and dismissed. Only death, rest, or dispel magic can remove it. This bug is still present as of v1.22.
- The Pig familiar is confirmed to be bugged and often will fail to summon for a small number of people. No workaround is known.
- Bat: Master gains +3 to Listen checks.
- Beetle: Master gains +1 hit point per character level.
- Cat: Master gains +2 to move silently and hide checks.
- Pig: Master gains +3 to diplomacy checks.
- Rabbit: Master gains +1 bonus to all saves.
- Rat: Master gains +2 to fortitude saves.
- Spider: Master gains +3 to bluff checks.
- Weasel: Master gains +2 to reflex saves.
The creature types will be defined in 2DA files, so the choices may be modified very easily (add/subtract).  Owls, ravens and snakes are not available, because the creature models were never made. 
- Familiars start at caster level one of their master with the evasion feat. At caster level four it is replaced with improved evasion and the familiar gains weapon proficiency (creature). Additional feats may be granted based on the creature type (e.g. a rabbit gains weapon finesse at caster level four).
- A familiar's hit points increase by advancement of the caster level of the class that grants the summon familiar feat. However, the additional hit points are only realized at every other caster level. Also, they do not share the benefits of spells that affect only their master.
- Obsidian has stated that familiars will not be "combat critters" in NWN2; they will not fight. The only way they can initiate an attack is by being a conduit for a touch spell from the master.  Familiars will actively avoid enemies and try to move away from their master during combat unless commanded to do otherwise. 
- Familiars may use stealth. 
- Unlike in NWN1, familiars do not soak XP. 
- Familiars will not have a collar inventory slot to accommodate magic items like a collar of spell resistance or collar of elemental protection. 
- Obsidian originally intended for familiars to be carried in a character's backpack, but that was changed and they're again associates like in NWN1. 
- There is a level 3 spell called "Enhance Familiar" that grants bonuses to a wizard's familiar (+2 to saves, attack and melee damage rolls, +2 dodge AC bonus. This spell has been cut from the game, however, it is still present in the toolset.
- Familiars can cast your divine spells but you have to tell them to cast the spells.
- Familiars in NWN provided an extra ally for combat, or other skills (such as lockpicking).
- A slain familiar in NWN caused damage to the owner, however no further penalties were applied and a replacement familiar could be summoned after resting.