msem-instigator

Poisonous 3 (Whenever this creature deals combat damage to a player, that player gets three poison counters.)
When Soulbreaker of Mautakesh enters, target poisoned player sacrifices a creature.

When Soulcarver enters, destroy up to one target non-Demon creature. If you do, create a 2/2 black Demon creature token and draw a card.

Other Spirits you control get +1/+1.
As long as a Spirit you control has flying, Soulcleaver has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
Haste

First strike, haste
Whenever Soulflare Nymph deals damage to a creature, exile that creature.

At the beginning of each end step, if you gained life this turn, put a +1/+1 counter on a creature you control.

Activated abilities of cards in your graveyard cost {2} less to activate.

Flash
Other Rogues you control get +1/+1.
Rogue spells you cast have flash.

Destroy target creature. Then if you control a Wizard, that creature's controller loses 1 life for each creature card in their graveyard.

Soulraving Hunt's power and toughness are each equal to the number of lands you control.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Flying
Whenever Souls of the Jury enters or an opponent fails a trial, create a 1/1 white Cleric creature token.

Mimic—Discard a card (Discard a card as a sorcery: This takes the shape of your choice.) [1/1]
[Shape 1] Menace
Soulshifter gets +1/+1 for each creature card in your graveyard. [1/1]
[Shape 2] Deathtouch
Whenever Soulshifter deals combat damage to a player, you may return target creature card from your graveyard to your hand. [2/2]

Soulsmoke Adept gets +1/+0 and has lifelink as long as it's embattled. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)

Sacrifice a creature: Soulsorrow Shade gets +2/+2 until end of turn.

Activated abilities of cards in your hand cost up to {1} less to activate. This effect can't reduce the amount of mana an ability costs to activate to less than one mana.

First strike
When Soulstone Commander enters, return target Soldier creature card from your graveyard to the battlefield. That creature is a Spirit in addition to its other types.

Flying
When Soulstone Redeemer dies, you may exile target creature. If you do, you gain life equal to its toughness.

Bulwark — Whenever Soulstone Servant attacks, if you control a creature with toughness 4 or greater, Soulstone Servant gets +2/+2 and gains flying until end of turn.

{3}, {T}, Sacrifice a non-Spirit creature: Create a 1/1 white Spirit creature token with flying.

Prowess, trample
During your turn, each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost plus “Pay X life, where X is this card's mana value.”

If target creature would leave the battlefield this turn, return it to its owner's hand instead.
Fuse (You may cast one or both halves of this card from your hand.)

Create a 1/1 blue Advisor creature token.
Draw a card.

Put a +1/+1 counter on each creature you control. (Then exile this card. You may cast the creature later from exile.)

Spend only black mana on X.
Any number of target players each draw X cards and lose X life.

Source Decay deals 2 damage to each opponent. Create two 1/1 colorless Servo artifact creature tokens.
Whenever a creature you control deals combat damage to a player, you may pay {2}{B}{R} and sacrifice it. If you do, return Source Decay from your graveyard to your hand.