Shalltear, The Bloodfallen

Lieutenant — If you control your Commander, whenever you gain life, put two +1/+1 counters on a creature under your control.

First Strike, Lifelink.

{1}{r}{b} Sacrifice a creature: This card gains Indestructible until the end of turn.
{t}{b} Sacrifice a creature: You gain life equal to its toughness.