One of the 6 classifications of Daeva (abominations) used by the Vigil. The Baali are those entities that have been possessed by other more powerful entities, usually entities from the Hollow. The Vigil are reluctant to treat the original soul as deceased, and will often attempt to drive the foreign entity out. If this does not work, they will try to imprison these beings in Tantharos but some entities from the Hollow are immune to the magic used to hold them in their cells. So finally if unable to imprison, the Vigil will kill the host.