Rustbuilt Legionnaire

Avenge 2 (As long as the number of creature cards in your graveyard is higher than an opponent's, this creature gets +2/+2.)
Sacrifice an artifact: Give Rustbuilt Legionnaire +0/+1 and Vigilance until the end of the turn.
Sacrifice a creature: Give Rustbuilt Legionnaire +1/+0 and First Strike until the end of the turn.