Killowat is an Honorary Titan from a completely separate Earth.
The main reason that Killowat was ever in this universe, was because Raven, while meditating, heard his cry for help from his own universe. In order to save him, Raven pulled him out of that universe and into her own. Killowat assisted the Teen Titans during many crises, such as that of Calling All Titans!, but Raven managed to find a way to mystically send him back to his own timeline, but erred and stranded him in yet another reality. Eventually, due to the combined efforts of Raven and Herald, Killowat was restored to his own world.