msem-instigator

Desert Slaughterer can't block.
{B}, Remove a +1/+1 counter from a creature you control: Return Desert Slaughterer from your graveyard to the battlefield with a +1/+1 counter on it.

Menace
Whenever Despair Scavenger attacks, you may have target creature get -1/-1 until end of turn.

Desperate Android enters tapped.
Whenever another artifact you control dies for the first time each turn, return Desperate Android from your graveyard to your hand.

{1}, Sacrifice a creature: Desperate Forsaken gets +1/+1 until end of turn. You gain 1 life.

Sacrifice a land: Desperate Ravager gets +2/+0 and gains haste until end of turn.

Haste
Whenever Desperate Reconnoiterer becomes untapped, scry 1.

Whenever Desperate Thief deals combat damage to a player, you may pay 2 life. If you do, draw a card.

Haste
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Assault {1}{B} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever a creature you control assaults, you may have target creature get -2/-2 until end of turn.

Menace
{1}{B}, Exile another three cards from your graveyard: Return Determined Explorer from your graveyard to your hand.

Whenever Determined Hero attacks, upgrade it. (Give it one of the listed counters it doesn't already have.)
• +1/+1
• Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

Trial 3 (As you cast this spell, an opponent of your choice may pay 3 life. If they don't, they fail the trial.)
When Devilish Undoer enters, if the trial was failed, return target creature card from your graveyard to your hand.

Flash
When Devious Naiad enters, exchange control of it and target creature until end of turn. Untap that creature. It gains haste until end of turn.

Whenever a storied permanent you control enters, you gain 1 life and each opponent loses 1 life. (Enchantments and legendary permanents are storied.)

Whenever a creature you control assaults, put a +1/+1 counter on Devoted Nomad.

Target player discards two cards.
Coalesce {8}{B} (You may cast this from your graveyard for {8}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)

Whenever Devourer of Legacy deals combat damage to a player, you may sacrifice it and choose a nonland card name. If you do, search that player's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Haste
{6}{R}: Diasune Immolator deals 4 damage to target player or planeswalker.

Hexproof

When Diligent Analyst enters, you may put an progress counter on a Project you control.
Diligent Analyst gets +1/+1 as long as you control two or more enchantments.

{3}{W}{W}: Detain target nonland permanent. (Until your next turn, that permanent can't attack or block and its activated abilities can't be activated.)

Disciple of Atemhar has lifelink as long as it has a +1/+1 counter on it.

Whenever another creature you control dies, each opponent loses 1 life and you gain 1 life. Then you may pay {B}. If you do, Disciple of Myriad Fates becomes a copy of that creature, except it has this ability.

{4}, {T}: Add {W}{U}{B}{R}{G}.

Whenever Dissenting Vikings attacks, if you control another Warrior, it gets +1/+0 until end of turn and deals 1 damage to defending player.