Possession

Possession is one of the twelve Schools of Alteration, and is defined as the ability to permanently connect two physical bodies by binding their Spirits together. Typically, this is done to join a human to a Solbound entity (such as a Beast or a Rune), such that the human gains the ability to influence the Sol around them. Originally, only exceptionally powerful being such as the Elder Beasts could perform Possession (a practice known as Familiar-Possession. Advances in the understanding of Sol eventually paved the way for Artificial Possession, however.  A practitioner of Possession is called a Possessor.