Frevah, Master Artificer

Indestructible
At the beginning of your upkeep, return target creature from your graveyard to the battlefield
tapped with a mana cost equal to or less than
your devotion to Swamp. When you do, you may
lose half of {x} life, rounded down where X is
your devotion to Swamp. If you don't, sacrifice
Frevah, Master Artificer.