Imprisoned for ten thousand years...banished from my own homeland...and now you dare enter my realm?
~ Illidan Stormrage, in the original cinematic trailer for World of Warcraft: The Burning Crusade.

An Outcast is basically another name for an exiled character or being. Unlike the Imprisoned Villain, an Outcast is banished without actually being imprisoned; sometimes, being exiled is seen as sufficient punishment in itself or they are away from civilization and society by choice. Many Outcast characters seek to return to their previous power or position; others are driven mad or embittered by it. Few, if any, embrace the state of exile.

Alternatively, an Outcast can be a tragic villain who is hated and feared by those around him/herself, forcing them into a life of relative isolation and/or wandering.

Sometimes, outcasts can be people who either got rejected by civilization and society, or they rejected civilization and society.