Erudii, Regent of Eternities

At the beginning of your first upkeep step each
turn, you get two additional upkeep steps.
At the beginning of your upkeep, if Erudii,
Regent of Eternities is in the graveyard or on the battlefield, you get an eternity counter.
{w}{b}, Sacrifice a creature: Return Erudii from
your graveyard to your hand. Then you gain life
equal to the number of eternity counters you
have and each opponent loses that much
life.