Vallender the Blood Alchemist

Flying, Lifelink
Whenever a creature an opponent controls dies, you may pay 2 life.
If you do, put a +1/+1 counter on Vallender, create a Blood Token
{T}, Sacrifice 3 Blood Tokens:Return target creature card from a graveyard to the battlefield under your control.
It gains haste. Exile it at the beginning of the next end step.