Avantor, Crown of Hell

+2: Sacrifice X creatures, then creatures you control have base power X and base toughness X-3 until end of turn.
+1: Create 2 0/1 Devil Servant creature tokens with "When this creature dies, target planeswalker gains 2 loyalty." and "sacrifice at any time."
-20: Target opponent loses the game if Avantor has gained loyalty this turn.