Familiars are creatures bonded through sorcery. Sorcerers use familiar relationships to perform magic without alerting the void. The Familiar is a channel through which magic related to a particular polar extreme is expressed. The sorcerer must also have a Material to express the opposite end of the polarity.
The levels of bonding are as follows:
Affinity: The sorcerer shares a bond with all examples of the familiar species. The sorcerer works some kind of polar magic through the manifestation of these animals.
Companion: The sorcerer shares a bond with one specific example of the species. The sorcerer can command magic to channel and manifest through the companion without alerting the void.
Alter: The sorcerer becomes the creature and while in that form can work polar magic directly through their body.
Avatar: The sorcerer allows another creature to use the sorcerer's body, whilst in this relationship the channeled being may work Dream Magic without alerting the void.