Dark Oak(real name:Lukas) is the father of Cosmo and a villain from Sonic universe.
He is the powerful leader of the Metarex, an army of bio-robots that scours the galaxy for the Planet Eggs, jewels that contain the life energies of their planets. Dark Oak has one large, green eye and carries a golden sword. His armor is composed of varied shades of purple, with a large green orb on his chest and two tattered halves of a black cape hanging from his shoulders. He is by far the most powerful of the cyborg aliens whose power surpasses even that of Super Sonic's, but his abilities are mostly unknown since he's never done much fighting onscreen. Aside from his weapon, all that's known about how he fights is that his speed is at-least on a level comparable with Super Sonic's. He is an intelligent schemer, but he never seems to take defeating Sonic and his friends seriously enough to fight them himself.
He is voiced by Matt Hoverman.
Allies and enemies
Allies: The Metarex, Cecliate, King Mungar, the Scaldaria Empire, Hell Councils
Enemies: Sonic, Tails, Knuckles, Amy Rose, Cosmo (his younger daughter), Galaxina (his eldest daughter), the Speed Crusade, the Miracle Elite, the Element Empire, the Children of the Autobots, the Mockingjay Crusaders, the Cosmic Empire