Avacyn, Angel of Light

Eminence - As long as Avacyn is in the command
zone or on the battlefield, other Angel spells you
cast cost {1} less to cast.
Flying, Lifelink, Haste
Whenever three or more Angels you control die,
or are put into your graveyard, exile Avacyn, then return her to the battlefield transformed under her owner's control.
{2}, Sacrifice an Angel: Gain 3 life.