Demongo

Demongo was one of Aku's most powerful minions and appears as a main antagonist in a Samurai Jack episode, XXIII.

Overview
He appears to have a pitch black body with skulls located at his torso (supposedly the essences of the warriors Demongo encountered in his past), red and black cloak, blue eyes, and a flaming blue fire located at the top of his head (indicating his hair). He is similar to his master, only except he is more cowardly. He does not fight in his confrontations, but instead summons the essence of the greatest warriors and beasts to fight for him while watching. Like Aku, he was originated from the Pit of Hate and was likely created by his master to collect the essence of warriors.

After Jack traveled back to his past and killed Aku, it is most likely Demongo would never exist in the future.