Darthos, Shifting Blade

Changeling Dethrone
Whenever Darthos attacks the player with the most
life or tied for the most life, exile target card from
that players graveyard. You may have Darthos
become a copy of a creature exiled this way until
the end of the turn. Darthos retains its name, abilities, and is still a legendary creature.
Whenever a creature you control with a +1/+1
counter on it dies, return that card to the battlefield
under your control at the beginning of the next
endstep.