The Oathkeeper

When the only other players are the king and
their teammates, reveal this role and you all win
the game.
When there is no King, if The Oathkeeper is face
down you lose the game.
If a Bandit were to cause the king to lose the
game, reveal The Oathkeeper.
While The Oathkeeper is revealed, Bandits
cannot win the game.
If you cause the last bandit to lose the game, you
win the game, otherwise, you lose the game.