Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp you control.

Dakmor Plague

Dakmor Plague deals 3 damage to each creature and each player.

Invoke Despair

Target opponent sacrifices a creature of their choice. If they can't, they lose 2 life and you draw a card. Then repeat this process for an enchantment and a planeswalker.

Syphon Mind

Each other player discards a card. You draw a card for each card discarded this way.

Soul Shred

Soul Shred deals 3 damage to target nonblack creature. You gain 3 life.

Night of Souls' Betrayal

Phthisis

Destroy target creature. Its controller loses life equal to its power plus its toughness.
Suspend 5—{1}{B} (Rather than cast this card from your hand, you may pay {1}{B} and exile it with five time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Extinction

Destroy all creatures of the creature type of your choice.

Jet Medallion

Black spells you cast cost {1} less to cast.

Monomania

Target player chooses a card in their hand and discards the rest.

Night's Whisper

Mutilate

All creatures get -1/-1 until end of turn for each Swamp you control.

Head Games

Target opponent puts the cards from their hand on top of their library. Search that player's library for that many cards. The player puts those cards into their hand, then shuffles.

Soul Feast

Target player loses 4 life and you gain 4 life.

Plague Wind

Destroy all creatures you don't control. They can't be regenerated.

Infernal Grasp

Destroy target creature. You lose 2 life.

Famine

Famine deals 3 damage to each creature and each player.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Final Death

Mind Warp

Look at target player's hand and choose X cards from it. That player discards those cards.

Nether Void

Whenever a player casts a spell, counter it unless that player pays {3}.

Unnerve

Wit's End

Ritual of Soot

Destroy all creatures with mana value 3 or less.

Rise of the Dread Marn

Create X 2/2 black Zombie Berserker creature tokens, where X is the number of nontoken creatures that died this turn.
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Languish

All creatures get -4/-4 until end of turn.

Biting Rain

All creatures get -2/-2 until end of turn.
Madness {2}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

No Mercy

Whenever a creature deals damage to you, destroy it.

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.