Spawn of Mayhem

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, this creature deals 1 damage to each player. Then if you have 10 or less life, put a +1/+1 counter on this creature.

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Reaper from the Abyss

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

Raphael, Fiendish Savior

Flying
Other Demons, Devils, Imps, and Tieflings you control get +1/+1 and have lifelink.
At the beginning of each end step, if a creature card was put into your graveyard from anywhere this turn, create a 1/1 red Devil creature token with "When this token dies, it deals 1 damage to any target."

Plague Drone

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

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Sol'kanar the Swamp King

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Whenever a player casts a black spell, you gain 1 life.

Shadowborn Demon

Flying
When this creature enters, destroy target non-Demon creature.
At the beginning of your upkeep, if there are fewer than six creature cards in your graveyard, sacrifice a creature.

Great Unclean One

Reverberating Summons — At the beginning of your end step, each opponent loses 2 life. Then for each opponent who has less life than you, create a 1/3 black Demon creature token named Plaguebearer of Nurgle.

Defiler of Souls

Flying
At the beginning of each player's upkeep, that player sacrifices a monocolored creature of their choice.

Devil

When this creature dies, it deals 1 damage to any target.

Chaos Defiler

Trample
Battle Cannon — When this creature enters or dies, for each opponent, choose a nonland permanent that player controls. Destroy one of them chosen at random.

Devils' Playground

Create four 1/1 red Devil creature tokens. They have "When this token dies, it deals 1 damage to any target."

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Soulcage Fiend

When this creature dies, each player loses 3 life.

When this creature dies, it deals 2 damage to each opponent.

Bedevil

Destroy target artifact, creature, or planeswalker.

Dance with Devils

Create two 1/1 red Devil creature tokens. They have "When this token dies, it deals 1 damage to any target."

Bloodletter of Aclazotz

Flying
If an opponent would lose life during your turn, they lose twice that much life instead. (Damage causes loss of life.)

Reign of the Pit

Each player sacrifices a creature of their choice. Create an X/X black Demon creature token with flying, where X is the total power of the creatures sacrificed this way.

Venomcrawler

Lifelink
Devourer of Souls — Whenever another creature dies, put a +1/+1 counter on this creature.

Bloodcrusher of Khorne

Trample
Devastating Charge — Other creatures you control have trample.

Asphyxiate

Razorjaw Oni

Renegade Demon

Total War

Whenever a player attacks with one or more creatures, destroy all untapped non-Wall creatures that player controls that didn't attack, except for creatures the player hasn't controlled continuously since the beginning of the turn.

Archfiend of Depravity

Flying
At the beginning of each opponent's end step, that player chooses up to two creatures they control, then sacrifices the rest.

Cast Down

Vampire Demon

Street Riot

During your turn, creatures you control get +1/+0 and have trample.

Bloodthirster

Flying, trample
Whenever this creature deals combat damage to a player, untap it. After this phase, there is an additional combat phase.
This creature can't attack a player it has already attacked this turn.