Nekroz, the Omnipotent

Eminence --- As long as Nekroz, the Omnipotent is in the command zone or on the battlefield, if an opponent has 20 or less life, creatures you control get +2/+1 and gain haste and deathtouch.
Lifelink, hexproof
Whenever Nekroz attacks, defending player loses X life and discards half of X cards rounded down, where X is its power.