Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)

Covenant of Blood deals 4 damage to any target and you gain 4 life.

Whenever one or more Demons you control attack a player, you draw a card and lose 1 life.

At the beginning of your end step, create a 5/5 black Demon creature token with flying, then mill two cards. If two cards that share all their card types were milled this way, sacrifice Demonic Covenant.

Flying

Whenever another nontoken creature you control dies, you may pay 2 life and exile it. If you do, create a token that's a copy of that creature, except it's 1/1 and has toxic 1. (Players dealt combat damage by it also get a poison counter.)

When Necromancer's Covenant enters, exile all creature cards from target player's graveyard, then create a 2/2 black Zombie creature token for each card exiled this way.

Zombies you control have lifelink.

Return target spell to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Menace

Whenever you gain life, you may pay . If you do, return target creature card from your graveyard to your hand.