Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Disfigure

Target creature gets -2/-2 until end of turn.

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Sign in Blood

Target player draws two cards and loses 2 life.

Night's Whisper

Chittering Rats

When Chittering Rats enters, target opponent puts a card from their hand on top of their library.

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Swamp

Cast Down

Diabolic Edict

Target player sacrifices a creature of their choice.

Thorn of the Black Rose

Deathtouch
When Thorn of the Black Rose enters, you become the monarch.

Cuombajj Witches

{T}: Cuombajj Witches deals 1 damage to any target and 1 damage to any target of an opponent's choice.