Demonic Covenant
From Duskmourn: House of Horror Commander set
Demonic Covenant
Kindred Enchantment — Demon
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 this enchantment.