Kaya, Tyrant's Bane

: This card can be your commander. Creatures your opponents control lose hexproof and indestructible, and cannot gain hexproof or indestructible.
+1: You may pay X life, if you do, target creature gets -X/-X until the end of the turn.
-6: Exile all cards in all graveyards, you gain life equal to the number of cards in exile, and each opponent loses life equal to that amount.