The alien being known as Beta Ray Bill is a Korbinite, whose homeworld was destroyed by the Asgardian demon Surtur. In his first battle with Thor, when Thor and his hammer were seperated, Beta Ray Bill was able to pick it up and claim it as his own. Odin declared that Thor and Bill should fight to the death to see who was worthy of holding Mjolnir and although Bill won, he chose not to kill Thor. Odin decreed that a new hammer should be made for Bill, this one called Stormbreaker, and Bill has become a champion of Asgard since.