Antichrist, Destructive Lord

Initiator
When Antichrist, Destructive Lord enters the battlefield, change the arena type to Mountain/Swamp type. Remove arena type when Antichrist, Destructive Lord dies or when a new Initiator enters the battlefield.
(Arenas give creatures of those color types +1/+1, Vigilance, First Strike, and becomes the same Creature type as the Initiator along with it's other Types)