Commander Cube

Choose a Background can be replaced by Partner
and vice versa. Any player can pick the Faceless
One or Prismatic Piper as their Commander.
If one or more creatures a player controls deals
combat damage to an opponent who is the
monarch and has the initiative, that player
chooses one and gains control of it.
A player who ventures into the dungeon while
not in a dungeon can enter any dungeon.