Vorae, Centaur Warrior

Player (Creatures blocked by Vorae gain trample until end of turn. Vorae cannot be removed from the battlefield.)
Whenever a creature enters the battlefield under your control, you may pay {g/w}. If you do, you gain life equal to that creature's toughness.
Mana Pool - {g} or {w} (During your untap step add {g} or {w} to your mana pool, this mana doesn't empty as steps, phases, and turns end.)