Krona

Krona was the renegade Guardian who, by obsession, created the ultimate being–the Anti-Monitor.

History
Eons ago on Maltus, Krona had an obsession with creating the ultimate being, so powerful, it could accomplish anything. Thus the Anti-Monitor was born, however the apparatus realized its superiority and started his conquest of absorbing matter. With his own creation against him, Krona somehow banished the Anti-Monitor to the Antimatter Universe, saving the universe from the latter's unsatiable hunger.