At the beginning of your upkeep, put two eon counters on Out of the Tombs, then
mill (To mill a card, a player puts the top card of their library into their graveyard.) cards equal to the number of eon counters on it.
If you would draw a card while your library has no cards in it, instead return a creature card from your graveyard to the battlefield. If you can't, you lose the game.