Riot Devils

Festival Crasher

Whenever you cast an instant or sorcery spell, Festival Crasher gets +2/+0 until end of turn.

Mountain

Brimstone Vandal

Menace (This creature can't be blocked except by two or more creatures.)
If it's neither day nor night, it becomes day as Brimstone Vandal enters.
Whenever day becomes night or night becomes day, Brimstone Vandal deals 1 damage to each opponent.

Blessing of Leeches

Flash
Enchant creature
At the beginning of your upkeep, you lose 1 life.
{0}: Regenerate enchanted creature.

Thraxodemon

{3}, {T}, Sacrifice another creature or artifact: Draw a card.

Hulking Devil

Body Dropper

Whenever you sacrifice another creature, put a +1/+1 counter on Body Dropper.
{B}{R}, Sacrifice another creature: Body Dropper gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Scourge Devil

When Scourge Devil enters, creatures you control get +1/+0 until end of turn.
Unearth {2}{R} ({2}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Immersturm Raider

When Immersturm Raider enters, you may discard a card. If you do, draw a card.

Scalding Devil

{2}{R}: Scalding Devil deals 1 damage to target player or planeswalker.

Betrothed of Fire

Enchant creature
Sacrifice an untapped creature: Enchanted creature gets +2/+0 until end of turn.
Sacrifice enchanted creature: Creatures you control get +2/+0 until end of turn.

Baleful Eidolon

Bestow {4}{B} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Enchanted creature gets +1/+1 and has deathtouch.

Swamp

Awoken Demon

Ecstatic Awakener

{2}{B}, Sacrifice another creature: Draw a card, then transform Ecstatic Awakener. Activate only once each turn.

Ecstatic Awakener // Awoken Demon

Forge Devil

When Forge Devil enters, it deals 1 damage to target creature and 1 damage to you.

Soulcage Fiend

When Soulcage Fiend dies, each player loses 3 life.

Aspect of Gorgon

Enchant creature
Enchanted creature gets +1/+3 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Pitchburn Devils

When Pitchburn Devils dies, it deals 3 damage to any target.

Chain Devil

Animate Chains — When Chain Devil enters, each player sacrifices a nontoken creature of their choice.

Aspect of Manticore

Flash
Enchant creature
When Aspect of Manticore enters, enchanted creature gains first strike until end of turn.
Enchanted creature gets +2/+0.

Binding Agony

Enchant creature
Whenever enchanted creature is dealt damage, Binding Agony deals that much damage to that creature's controller.

Havoc Devils

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

Hobblefiend

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
{1}, Sacrifice another creature: Put a +1/+1 counter on Hobblefiend.

Kardur, Doomscourge

When Kardur, Doomscourge enters, until your next turn, creatures your opponents control attack each combat if able and attack a player other than you if able.
Whenever an attacking creature dies, each opponent loses 1 life and you gain 1 life.

Mayhem Patrol

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mayhem Patrol attacks, target creature gets +1/+0 until end of turn.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Demonic Stench

Each creature that blocked this turn gets -1/-1 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Hezrou

Whenever one or more creatures you control become blocked, each blocking creature gets -1/-1 until end of turn.

Hezrou // Demonic Stench

Renegade Demon

Soulstinger

When Soulstinger enters, put two -1/-1 counters on target creature you control.
When Soulstinger dies, you may put a -1/-1 counter on target creature for each -1/-1 counter on Soulstinger.

Rafter Demon

Spectacle {3}{B}{R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
When Rafter Demon enters, if its spectacle cost was paid, each opponent discards a card.

Bitter Reunion

When Bitter Reunion enters, you may discard a card. If you do, draw two cards.
{1}, Sacrifice Bitter Reunion: Creatures you control gain haste until end of turn.

Arcane Teachings

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +2/+2 and has "{T}: This creature deals 1 damage to any target."

Aspect of Lamprey

Enchant creature you control
When Aspect of Lamprey enters, target opponent discards two cards.
Enchanted creature has lifelink.

Footlight Fiend

When Footlight Fiend dies, it deals 1 damage to any target.

Torch Fiend

{R}, Sacrifice Torch Fiend: Destroy target artifact.

Bloodshed Fever

Enchant creature
Enchanted creature attacks each combat if able.

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.