Battlegrounds Tank

When Battlegrounds tank enters the battlefield choose {x} Target creatures where {x} is the number of enchantments you control. Those creatures are now inside Battlegrounds tank and only do damage to other creatures inside Battlegrounds Tank, until either only one is left or Battlegrounds tank is destroyed. The winner becomes the Monarch. If Battlegrounds tank is destroyed all creatures inside Battlegrounds Tank are Exiled.

At the start of your upkeep as long as there is a creature in battlegrounds tan