msem-instigator

Doomsday Horde enters tapped unless it was foreshadowed.
When Doomsday Horde dies, search your library for a card, put it into your hand, then shuffle.
Foreshadow {3}{B}{B}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

Whenever Doomsower or another Human you control dies, you draw a card and you lose life equal to that creature's power.

When Doomstep Giant enters, each player sacrifices a land.

Enchant creature
When Double Arming enters, put a +1/+1 counter on enchanted creature.
Enchanted creature has menace.
{5}: Return Double Arming to its owner's hand.

Whenever another creature dies, you gain 1 life.
At the beginning of each end step, if you gained 3 or more life this turn, transform Dowager of Traublassen.

This spell costs {2} less to cast if you control a Rogue.
Target opponent discards two cards.

Enchant opponent
When Down with the Ship enters, enchanted player discards a card unless they sacrifice a creature.
{1}{B}, Sacrifice Down with the Ship: Return target creature card from your graveyard to your hand.

Return target creature card from your graveyard to your hand.
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

Menace
Whenever Dragon's Twisted Shadow attacks and isn't blocked, it gets +4/+0 until end of turn.

Exile target creature with power 3 or less. You gain 3 life.

Drakon Nightshade can't block.
When Drakon Nightshade dies, scry 1.

Target creature gets -2/-1 until end of turn. When it dies this turn, its controller loses 5 life.

{1}, Sacrifice another creature: Put a +1/+1 counter on Dread Cabalist and on up to one target legendary creature. Activate only as a sorcery.

When Dread Elk dies, put a +1/+1 counter on target creature you control. If that creature is a Zombie, put two +1/+1 counters on it instead.
Foreshadow {5}{B} (You may cast this spell for its foreshadow cost. If you do, also trigger its “dies” abilities when it enters.)

This spell costs {1} less to cast for each card put into your graveyard from anywhere this turn.
At the beginning of each player's upkeep, that player loses 1 life, discards a card, and sacrifices a creature.

Deathtouch
Whenever Dreadful Gorgon attacks, target attacking creature with lesser power gains deathtouch until end of turn.

When this creature enters, you may sacrifice a creature. If you do, you draw a card and you lose 1 life.
Arise {2}{B} ({2}{B}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

Flying
When Dreadworld Demon enters, each opponent may have you draw a card. Each player who doesn't loses 3 life. You gain life equal to the life lost this way.

Whenever a spell or ability causes an opponent to draw a card, draw a card unless that player pays 1 life.

{1}{B}, Mill three cards: Return Dredging Aberration from your graveyard to your hand.

Return up to one target creature card from your graveyard to the battlefield tapped. You gain 2 life.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

When Dregscape Wretch dies, create a 2/2 black Zombie creature token.

When Driver of Hordes enters, create a tapped 2/2 black Zombie creature token.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the end step or if it would leave the battlefield. Unearth only as a sorcery.)

This spell costs {X} less to cast, where X is the number of card types among cards in your graveyard.
Surveil 3, then you draw three cards. You lose 3 life.

{T}, Sacrifice a creature or land: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.