Hexiis, The Memory

+2: Hexiis deals damage to target player equal to half the number of the cards in his or her graveryard rounded down. Each opponent discards a card.
-X: Hexiis deals X damage to target opponent, then that player puts that many cards from his or her library into his or her graveyard.
: As long as your devotion to blue, red and black is less than eight, you can't activate any of Hexiis' abilities and he can't be attacked.