The spirit (usually a Bane) may possess a living being or inanimate object. Possession requires a successful Gnosis roll (difficulty of the victim's Willpower). The number of successes equals the speed with which possession occurs as per the following chart:
During the time it takes to possess its victim, the spirit will find a dark, isolated part of the Umbra (usually a Blight) and remain there, concentrating on the possession. During this time, the spirit can take no other action. If it engages in spirit combat, the possessive link is broken. Others of their kind often guard possessing spirits, in order to ensure that the possession process continues undisturbed.
A spirit that has possessed a victim is able to manifest certain characteristics and abilities through the vessel of the victim's body. Such hapless humans are known as fomori (see Chapter Nine). This relationship is permanent - as long as the human host lives, that is.