| The subject of this article is non-canonical.|
While created as part of licensed material, it has not been confirmed as part of the "real" Buffyverse.
Cassia's family had been previously killed by vampires, and she considered her Watcher cold and emotionless. Turned into a slaypire, Cassia staked her sire and continued to slay vampires, but also prey on and despite humans. The Watchers Council never knew about her turning, considering her dead. She has assumed various names through the ages, such as Callia in late 1800, when she met Spike at a saloon; Catia in 1950, Poland; and Celina in 2000, Sunnydale, when she challenged and attempted to convince Buffy Summers to join her as a vampire. She was eventually defeated and staked by Buffy.