Balroth the Mourner

Balroth, the Mourner costs {1}{b} less to cast for each creature that died under your control this turn.
When Balroth enters the battlefield, return x target creatures from your graveyard to your hand, where x is the amount of mana you paid to cast Balroth.
Mourning for what had been lost, Balroth found power within himself; his friends would be returned to him.