Corvo Cornelius, heir to Death

Whenever you gain life mill that many cards.
Whenever Corvo Cornelius attacks you may
exile a card from your graveyard. If it’s a
creature card Out a +1/+1 counter on Corvo, if
it is a land add two mana of any color, you do not
lose this mana as steps and phases end. If it is a
non-creature non-land, discard a card then
draw a card.