Naiba the String Puller

Extort (Whenever you cast a spell, you may pay {w/b}. If you do, each opponent loses 1 life and you gain
that much life.)
Whenever a creature enters the battlefield from
the graveyard, each opponent loses 1 life and you
gain that much life.
{x}{w}{b}: Return target creature card from your
graveyard with converted mana cost X or less and
put it onto the battlefield. X can't be greater than
3.