Flying

When Abhorrent Overlord enters the battlefield, create a number of 1/1 black Harpy creature tokens with flying equal to your devotion to black. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

At the beginning of your upkeep, sacrifice a creature.

Whenever you sacrifice a permanent, put a +1/+1 counter on Blood Aspirant.

{1}{R}, {T}, Sacrifice a creature or enchantment: Blood Aspirant deals 1 damage to target creature. That creature can't block this turn.

Sacrifice another creature: Blood Bairn gets +2/+2 until end of turn.

Menace

Goaded creatures your opponents control can't block.

Whenever you cast a noncreature spell, goad target creature an opponent controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Flying, trample

Whenever Demon of Loathing deals combat damage to a player, that player sacrifices a creature.

Flying

At the beginning of your upkeep, sacrifice a creature other than Demonic Taskmaster.

At the beginning of your end step, you may sacrifice a creature. If you do, look at the top X cards of your library, where X is that creature's mana value. You may put a creature card from among them onto the battlefield. Put the rest on the bottom of your library in a random order.

Flying

Whenever Lord of the Void deals combat damage to a player, exile the top seven cards of that player's library, then put a creature card from among them onto the battlefield under your control.

First strike, deathtouch

Master of Cruelties can only attack alone.

Whenever Master of Cruelties attacks a player and isn't blocked, that player's life total becomes 1. Master of Cruelties assigns no combat damage this combat.

+2: Each opponent loses 1 life. You gain life equal to the life lost this way.

-2: Create a 5/5 black Demon creature token with flying. You lose 2 life.

-8: You get an emblem with "{1}{B}, Sacrifice a creature: You gain X life and draw X cards, where X is the sacrificed creature's power."

Ob Nixilis of the Black Oath can be your commander.

Cumulative upkeep--Sacrifice a creature. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Flying

Rot Fly -- If an opponent would gain life, that player loses that much life instead.

Flying, trample

Whenever Rakdos the Defiler attacks, sacrifice half the non-Demon permanents you control, rounded up.

Whenever Rakdos deals combat damage to a player, that player sacrifices half the non-Demon permanents they control, rounded up.

Flying, trample

When Rakdos, the Showstopper enters the battlefield, flip a coin for each creature that isn't a Demon, Devil, or Imp. Destroy each creature whose coin comes up tails.

Flying, trample

Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.

Flying

Morbid -- At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.

Flying

Whenever you sacrifice a creature, target opponent sacrifices a creature.

When Shadowgrange Archfiend enters the battlefield, each opponent sacrifices a creature with the greatest power among creatures they control. You gain life equal to the greatest power among creatures sacrificed this way.

Madness--{2}{B}, Pay 8 life. (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

As an additional cost to cast this spell, sacrifice all creatures you control.

Soulblast deals damage to any target equal to the total power of the sacrificed creatures.

Flying

Whenever Tomb Blade deals combat damage to a player, that player loses life equal to the number of creatures they control unless they sacrifice a creature.

Unearth {6}{B}{B}

As an additional cost to cast this spell, you may sacrifice any number of creatures. This spell costs {2} less to cast for each creature sacrificed this way.

When Torgaar, Famine Incarnate enters the battlefield, up to one target player's life total becomes half their starting life total, rounded down.

Flying, trample

As Tyrannical Pitlord enters the battlefield, choose another creature you control.

The chosen creature gets +3/+3 and has flying.

When Tyrannical Pitlord leaves the battlefield, sacrifice the chosen creature.

First strike

Sacrifice Vampire Hexmage: Remove all counters from target permanent.

Flying, trample

At the beginning of your upkeep, sacrifice a creature other than Xathrid Demon, then each opponent loses life equal to the sacrificed creature's power. If you can't sacrifice a creature, tap Xathrid Demon and you lose 7 life.