Walt

Walt was a hunter whom Dean Winchester apparently knew. He and Roy came back for revenge after finding out Sam started the Apocalypse.

Season 5
After the Apocalypse was triggered, Roy and Walt learned about Sam Winchester's role in starting it. Seeking retribution, they tracked the Winchesters down to their motel and held them at gunpoint. Dean recognized them both despite the masks they wore. Before Sam could explain himself, Walt shot and killed him. He then ordered Roy to kill Dean too. When Roy hesitated to do so, Walt did it himself, but not before Dean warned him he was going to be pissed when he came back.

Appearances

 * Season 5
 * Dark Side of the Moon

Trivia

 * It's unknown what happened to Roy and Walt after the events of the episode. Dean may or may not have gotten his revenge on them as he promised.
 * They share the same name as the Disney brothers.