Archfiend of the Dross

Flying
This creature enters with four oil counters on it.
At the beginning of your upkeep, remove an oil counter from this creature. Then if it has no oil counters on it, you lose the game.
Whenever a creature an opponent controls dies, its controller loses 2 life.

Chain Assassination

Freerunning {1}{B} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Destroy target creature. If another creature died this turn, draw a card.

Back for Seconds

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Return up to two target creature cards from your graveyard to your hand. If this spell was bargained, you may put one of those cards with mana value 4 or less onto the battlefield instead of putting it into your hand.

Tomb of Urami

{T}: Add {B}. Tomb of Urami deals 1 damage to you if you don't control an Ogre.
{2}{B}{B}, {T}, Sacrifice all lands you control: Create Urami, a legendary 5/5 black Demon Spirit creature token with flying.

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

Barrier of Bones

Defender
When this creature enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Cradle of the Accursed

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Create a 2/2 black Zombie creature token. Activate only as a sorcery.

Reactor Raid

You may sacrifice an artifact or creature. If you do, draw two cards. (Then exile this card. You may play the land later from exile.)

Midgar, City of Mako

Midgar, City of Mako // Reactor Raid

Realm of Koh

This land enters tapped unless you control a basic land.
{T}: Add {B}.
{3}{B}, {T}: Create a 1/1 colorless Spirit creature token with "This token can't block or be blocked by non-Spirit creatures."

Heartless Summoning

Creature spells you cast cost {2} less to cast.
Creatures you control get -1/-1.

Abhorrent Overlord

Flying
When this creature enters, 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.

Blood Funnel

Noncreature spells you cast cost {2} less to cast.
Whenever you cast a noncreature spell, counter that spell unless you sacrifice a creature.

Ammit Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
Whenever an opponent casts a spell, put a -1/-1 counter on this creature.
Whenever this creature deals combat damage to a player, remove all -1/-1 counters from it.

Dockside Chef

{1}{B}, Sacrifice an artifact or creature: Draw a card.

Serrated Scorpion

When this creature dies, it deals 2 damage to each opponent and you gain 2 life.