Demonic Counsel

Search your library for a Demon card, reveal it, put it into your hand, then shuffle.
Delirium — If there are four or more card types among cards in your graveyard, instead search your library for any card, put it into your hand, then shuffle.

Doomsday Excruciator

Flying
When this creature enters, if it was cast, each player exiles all but the bottom six cards of their library face down.
At the beginning of your upkeep, draw a card.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Singularity Rupture

Destroy all creatures, then any number of target players each mill half their library, rounded down.

Tasha, the Witch Queen

Whenever you cast a spell you don't own, create a 3/3 black Demon creature token.
+1: Draw a card. For each opponent, exile up to one target instant or sorcery card from that player's graveyard and put a page counter on it.
−3: You may cast a spell from among cards in exile with page counters on them without paying its mana cost.
Tasha, the Witch Queen can be your commander.

Diabolic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Reaper from the Abyss

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

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis.

Goremand

As an additional cost to cast this spell, sacrifice a creature.
Flying
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
When this creature enters, each opponent sacrifices a creature.

Waterfront District

This land enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice this land: Draw a card.

Ritual Chamber

When you unlock this door, create a 6/6 black Demon creature token with flying.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Unholy Annex

At the beginning of your end step, draw a card. If you control a Demon, each opponent loses 2 life and you gain 2 life. Otherwise, you lose 2 life.
(You may cast either half. That door unlocks on the battlefield. As a sorcery, you may pay the mana cost of a locked door to unlock it.)

Unholy Annex // Ritual Chamber

Fading Hope

Return target creature to its owner's hand. If its mana value was 3 or less, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Night's Whisper

Arbiter of Woe

As an additional cost to cast this spell, sacrifice a creature.
Flying
When this creature enters, each opponent discards a card and loses 2 life. You draw a card and gain 2 life.

Soul Read

Choose one —
• Counter target spell unless its controller pays {4}.
• Draw two cards.

Demonic Taskmaster

Flying
At the beginning of your upkeep, sacrifice a creature other than this creature.

Demon Wall

Defender
Menace (This creature can't be blocked except by two or more creatures.)
As long as this creature has a counter on it, it can attack as though it didn't have defender.
{5}{B}: Put two +1/+1 counters on this creature.

Remand

Counter target spell. If that spell is countered this way, put it into its owner's hand instead of into that player's graveyard.
Draw a card.

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Thriving Moor

This land enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Infernal Vessel

When this creature dies, if it wasn't a Demon, return it to the battlefield under its owner's control with two +1/+1 counters on it. It's a Demon in addition to its other types.

Submerged Boneyard

This land enters tapped.
{T}: Add {U} or {B}.

Gurmag Rakshasa

Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, target creature an opponent controls gets -2/-2 until end of turn and target creature you control gets +2/+2 until end of turn.

Bloodsoaked Altar

{T}, Pay 2 life, Discard a card, Sacrifice a creature: Create a 5/5 black Demon creature token with flying. Activate only as a sorcery.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Etched Host Doombringer

When this creature enters, choose one —
• Target opponent loses 2 life and you gain 2 life.
• Choose target battle. If an opponent protects it, remove three defense counters from it. Otherwise, put three defense counters on it.

Delightful Discovery

This spell costs {1} less to cast for each spell your opponents have cast this turn.
Scry 2, then draw two cards. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Rot-Curse Rakshasa

Trample
Decayed (This creature can't block. When it attacks, sacrifice it at end of combat.)
Renew — {X}{B}{B}, Exile this card from your graveyard: Put a decayed counter on each of X target creatures. Activate only as a sorcery.

Miasma Demon

Flying
When this creature enters, you may discard any number of cards. When you do, up to that many target creatures each get -2/-2 until end of turn.

Treno, Dark City

Bringer of the Last Gift

Flying
When this creature enters, if you cast it, each player sacrifices all other creatures they control. Then each player returns all creature cards from their graveyard that weren't put there this way to the battlefield.

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Indulgent Tormentor

Flying
At the beginning of your upkeep, draw a card unless target opponent sacrifices a creature of their choice or pays 3 life.

Island

Overflowing Insight

Tyrannical Pitlord

Flying, trample
As this creature enters, choose another creature you control.
The chosen creature gets +3/+3 and has flying.
When this creature leaves the battlefield, sacrifice the chosen creature.

Thriving Isle

This land enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.