Tatianna Bellefleur

Defender, Deathtouch, Protection from Red, Partner (The Heirs)
{t}{x}: Return X creatures that have died this turn to the battlefield. You gain 1 life for each creature returned from the graveyard this turn. Tatianna, Daughter of Ravens doesn't untap on your next untap step.
If you have gained 15 or more life in a turn, you may untap Tatianna, Daughter of Ravens. This can occur once per turn.