Detonator Orgun is a 1991 OAV series produced by AIC. Two English dubs were made - one in the UK by Manga Entertainment, which was the three episodes combined into a movie, and one in the US by U.S. Manga Corps.
Synopsis
Fleeing from his own race, Orgun—an alien being with superhuman abilities and unearthly weapons—travels to Earth to find an answer to his origin. There, he bonds with a young man named Tomoru to defend Earth against the Evoluders, who seek nothing but destruction of other civilizations.