Baneful Omen

You may reveal this card from your opening hand. If you do, at the beginning of the first upkeep, each opponent loses 3 life, then you gain life equal to the life lost this way.

Flying, lifelink

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

At the beginning of your end step, draw a card. If you control a Demon, each opponent loses 2 life and you gain 2 life. Otherwise, you lose 2 life.

(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Flying

Your opponents can't gain life.

At the beginning of each end step, each opponent loses life equal to the life that player lost this turn. (Damage causes loss of life.)

At the beginning of your upkeep, if you have no cards in hand, each opponent loses 2 life.

At the beginning of each opponent's upkeep, if that player has no cards in hand, they lose 2 life.

At the beginning of each opponent's upkeep, you manifest the top card of that player's library. (Put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Whenever a creature you control but don't own dies, its owner loses 2 life and you gain 2 life.