Davriel, Arcane Thief

: Whenever an opponent discards a card, you draw a card and gain 1 life, then put a loyalty counter on Davriel, Arcane Thief.
-2: Target opponent reveals their hand to you. Choose a nonland card from their hand, you may cast that card by paying mana of any color.
-7: Each opponent discards their hand and loses X life, X equal to the number of cards that opponent discarded.