Zero, the Betrayer

+1: Discard a card, then draw a card. If the cards share a color, you may repeat this ability.
0: Increase Zero, the Betrayer's loyalty by 1 for each different type of creature you control. For each loyalty raised, gain 1 life.
-6: Destroy all creatures on the battlefield except for X target creatures where X is the loyalty number on Zero after activating this ability.