At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.
5 /
4
{6}{B}{B}
Archfiend of Despair
Creature - Demon
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.)
6 /
6
{4}{B}{B}
Carnifex Demon
Creature - Phyrexian Demon
Flying
Carnifex Demon enters the battlefield with two -1/-1 counters on it.
{B}, Remove a -1/-1 counter from Carnifex Demon: Put a -1/-1 counter on each other creature.
6 /
6
{3}{B}{B}{B}
Demon of Dark Schemes
Creature - Demon
Flying
When Demon of Dark Schemes enters the battlefield, all other creatures get -2/-2 until end of turn.
Whenever another creature dies, you get {E} (an energy counter).
{2}{B}, Pay {E}{E}{E}{E}: Put target creature card from a graveyard onto the battlefield under your control tapped.
5 /
5
{4}{B}{B}
Demonlord Belzenlok
Legendary Creature - Elder Demon
Flying, trample
When Demonlord Belzenlok enters the battlefield, exile cards from the top of your library until you exile a nonland card, then put that card into your hand. If the card's mana value is 4 or greater, repeat this process. Demonlord Belzenlok deals 1 damage to you for each card put into your hand this way.
6 /
6
{3}{B}{B}
Doom Whisperer
Creature - Nightmare Demon
Flying, trample
Pay 2 life: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
6 /
6
{7}{B}{B}{B}
Dread Cacodemon
Creature - Demon
When Dread Cacodemon enters the battlefield, if you cast it from your hand, destroy all creatures your opponents control, then tap all other creatures you control.
8 /
8
{4}{B}{B}
Harvester of Souls
Creature - Demon
Deathtouch
Whenever another nontoken creature dies, you may draw a card.
5 /
5
{5}{B}{B}
Havoc Demon
Creature - Demon
Flying
When Havoc Demon dies, all creatures get -5/-5 until end of turn.
5 /
5
{5}{B}{B}
Herald of Anguish
Creature - Demon
Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Flying
At the beginning of your end step, each opponent discards a card.
{1}{B}, Sacrifice an artifact: Target creature gets -2/-2 until end of turn.
5 /
5
{4}{B}{B}
Kothophed, Soul Hoarder
Legendary Creature - Demon
Flying
Whenever a permanent owned by another player is put into a graveyard from the battlefield, you draw a card and you lose 1 life.
6 /
6
{4}{B}{B}{B}
Lord of the Void
Creature - Demon
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.
7 /
7
{3}{B}{R}
Master of Cruelties
Creature - Demon
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.
1 /
4
{2}{B}{B}
Mindwrack Demon
Creature - Demon
Flying, trample
When Mindwrack Demon enters the battlefield, mill four cards.
Delirium -- At the beginning of your upkeep, you lose 4 life unless there are four or more card types among cards in your graveyard.
4 /
5
{4}{B}{B}
Nefarox, Overlord of Grixis
Legendary Creature - Demon
Flying
Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever Nefarox, Overlord of Grixis attacks alone, defending player sacrifices a creature.
5 /
5
{4}{B}{B}
Ob Nixilis, Unshackled
Legendary Creature - Demon
Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.
4 /
4
{5}{B}{B}
Overseer of the Damned
Creature - Demon
Flying
When Overseer of the Damned enters the battlefield, you may destroy target creature.
Whenever a nontoken creature an opponent controls dies, create a tapped 2/2 black Zombie creature token.
5 /
5
{5}{B}{B}{B}
Pestilence Demon
Creature - Demon
Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.
7 /
6
{B}{B}{R}{R}
Rakdos, Lord of Riots
Legendary Creature - Demon
You can't cast this spell unless an opponent lost life this turn.
Flying, trample
Creature spells you cast cost {1} less to cast for each 1 life your opponents have lost this turn.
6 /
6
{4}{B}{R}
Rakdos, the Showstopper
Legendary Creature - Demon
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.
6 /
6
{5}{B}{B}{B}
Razaketh, the Foulblooded
Legendary Creature - Demon
Flying, trample
Pay 2 life, Sacrifice another creature: Search your library for a card, put that card into your hand, then shuffle.
8 /
8
{3}{B}{B}{B}
Reaper from the Abyss
Creature - Demon
Flying
Morbid -- At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.
6 /
6
{5}{B}{B}
Rune-Scarred Demon
Creature - Demon
Flying
When Rune-Scarred Demon enters the battlefield, search your library for a card, put it into your hand, then shuffle.
6 /
6
{4}{B}{B}
Sower of Discord
Creature - Demon
Flying
As Sower of Discord enters the battlefield, choose two players.
Whenever damage is dealt to one of the chosen players, the other chosen player also loses that much life.
6 /
6
{2}{B}{B}
Spawn of Mayhem
Creature - Demon
Spectacle {1}{B}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Flying, trample
At the beginning of your upkeep, Spawn of Mayhem deals 1 damage to each player. Then if you have 10 or less life, put a +1/+1 counter on Spawn of Mayhem.
4 /
4
{5}{B}{B}
Abhorrent Overlord
Creature - Demon
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.
6 /
6
{2}{B}{B}
Abyssal Persecutor
Creature - Demon
Flying, trample
You can't win the game and your opponents can't lose the game.
6 /
6
{3}{B}{B}
Bloodgift Demon
Creature - Demon
Flying
At the beginning of your upkeep, target player draws a card and loses 1 life.
5 /
4
{3}{B}{B}{R}
Defiler of Souls
Creature - Demon
Flying
At the beginning of each player's upkeep, that player sacrifices a monocolored creature.
5 /
5
{2}{B}{B}
Demon of Catastrophes
Creature - Demon
As an additional cost to cast this spell, sacrifice a creature.
Flying, trample
6 /
6
{3}{B}{B}
Demon of Wailing Agonies
Creature - Demon
Flying
Lieutenant -- As long as you control your commander, Demon of Wailing Agonies gets +2/+2 and has "Whenever Demon of Wailing Agonies deals combat damage to a player, that player sacrifices a creature."
4 /
4
{2}{B}{B}
Desecration Demon
Creature - Demon
Flying
At the beginning of each combat, any opponent may sacrifice a creature. If a player does, tap Desecration Demon and put a +1/+1 counter on it.
6 /
6
{5}{B}{B}
Eater of Hope
Creature - Demon
Flying
{B}, Sacrifice another creature: Regenerate Eater of Hope.
{2}{B}, Sacrifice two other creatures: Destroy target creature.
6 /
4
{2}{B}{B}{R}{R}
Rakdos the Defiler
Legendary Creature - Demon
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.
7 /
6
{4}{B}{B}{B}{B}
Reiver Demon
Creature - Demon
Flying
When Reiver Demon enters the battlefield, if you cast it from your hand, destroy all nonartifact, nonblack creatures. They can't be regenerated.