Cerberus

Cerberus (greek: Κέρβερος) is a large multi-headded hound. While usually depicted with three heads, this is not exclusively the case. Cerberos is also at times depicted with a serpent's tail, or snakes growing out of it's body, and at times with a mane of fire, or fire-breathing abilities. Cerberos guards the gates of the underworld.

Source
Cerberus is the offspring of Typhon and Echidna. Cerberus' siblings are the Chimera, Hydra, Sphinx and Orthrus. The earliest mention is in Hesiod's poem Theogony around 700 BC.

Media
Cerberus appear in the following media:

Games

 * Gems of War
 * Gems of War
 * Gems of War
 * Gems of War
 * Gems of War