Nether Traitor

Haste
Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever another creature is put into your graveyard from the battlefield, you may pay {B}. If you do, return Nether Traitor from your graveyard to the battlefield.

Nether Spirit

At the beginning of your upkeep, if Nether Spirit is the only creature card in your graveyard, you may return Nether Spirit to the battlefield.

Dark Bargain

Look at the top three cards of your library. Put two of them into your hand and the other into your graveyard. Dark Bargain deals 2 damage to you.

Swamp

Malicious Affliction

Morbid — When you cast this spell, if a creature died this turn, you may copy Malicious Affliction and may choose a new target for the copy.
Destroy target nonblack creature.

Skirsdag High Priest

Morbid — {T}, Tap two untapped creatures you control: Create a 5/5 black Demon creature token with flying. Activate only if a creature died this turn.

Dark Prophecy

Whenever a creature you control dies, you draw a card and you lose 1 life.

Infernal Tribute

{2}, Sacrifice a nontoken permanent: Draw a card.

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Sign in Blood

Target player draws two cards and loses 2 life.

Priest of the Blood Rite

When Priest of the Blood Rite enters, create a 5/5 black Demon creature token with flying.
At the beginning of your upkeep, you lose 2 life.

Scheming Symmetry

Choose two target players. Each of them searches their library for a card, then shuffles and puts that card on top.

Barter in Blood

Each player sacrifices two creatures of their choice.

Tormented Soul

Tormented Soul can't block and can't be blocked.

Disciple of Phenax

When Disciple of Phenax enters, target player reveals a number of cards from their hand equal to your devotion to black. You choose one of them. That player discards that card. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Leechridden Swamp

({T}: Add {B}.)
Leechridden Swamp enters tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Reaper from the Abyss

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