Cerberus

Appearances

 * Megami Tensei
 * Shin Megami Tensei
 * Shin Megami Tensei III: Nocturne
 * Devil Summoner: Raidou Kuzunoha vs. The Soulless Army: Pyro Class Demon
 * Persona 2: Eternal Punishment: Fortune Arcana Persona

In Shin Megami Tensei
In Shin Megami Tensei, the protagonist's dog, Pascal, becomes a Cerberus after fusing itself with a demon. It aids it's master in one battle before disappearing through a teleporter. The Pascal cerberus recognizes it's old master later in the game and rejoins him.