incorruptible champion

incorruptible champion's power and toughness is
equal to the total number of cards in exile.
when incorruptible champion enters the
battlefield or attacks, exile target card from a
graveyard, if incorruptible champion is white
you gain one life, if it is black target opponent
loses 1 life
Escape - {b}{b}, Exile two other cards from your graveyard
When incorruptible champion escapes
it's color changes from black to white