King Darkoan (魔界王ダークロード "Makai King Darklord") is the ruler of the Demon Realm in Gargoyle's Quest. Breager sealed his powers, and without it he was weakened to the point he cannot even move, and was assumed to be dead, trapped within his throne room. Barone Jark asks Firebrand to help him by giving the king the Candle of the Poltergeist.
After defeating Bellzemos, Firebrand enters the throne room and uses the Candle of the Poltergeist on the king and he gains enough power to talk. Afterwards he lends his remaining power to Firebrand. His strength, what is left of it, increases Firebrand's Wings and Nails stats.
Another alias may be King Barr.
He looks incredibly similar to Hades