Grenxa, Pawn of Sheoldred

Grenxa, Pawn of Sheoldred has +1/+1 equal to
your devotion to Phyrexian Black.
At the beginning of each opponent's upkeep,
they sacrifice a creature.
If your devotion to Phyrexian Black is equal
to or over 10, at the beginning of your upkeep,
return target creature from your graveyard to the battlefield.