msem-instigator

Whenever Gorran Hunter perseveres, target creature gets -1/-1 until end of turn. (A creature perseveres when it survives damage.)

When Graygulch Lurker dies, target opponent loses 2 life.

Haste
Whenever a player loses life, that player gains control of Graygulch Revenant.

Flying
When Greater Swooprat enters, creatures your opponents control get -1/-1 until end of turn.

When Grisly Reaper enters, you may exile a creature card from your graveyard. When you do, create a 1/1 black Skeleton creature token.

When Hand of the Murder enters, if you control a creature with a +1/+1 counter on it, create a 1/1 black Bird creature token with flying.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Haploc Blooddrinker becomes blocked, it gains lifelink until end of turn.

Menace
Art of war — At the beginning of your end step, if Hashiro's Infiltrator dealt damage to an opponent this turn, that player discards a card.

Menace
Sacrifice a Goblin: Heartless Warleader gets +2/+2 until end of turn.

When Hextwister Hare enters, if you control another Shaman or there's a Shaman card in your graveyard, each opponent discards a card.

Menace
Other Zombies you control get +1/+1.
Whenever a Zombie you control dies, each opponent loses 1 life.

Flying
Morph {4}{R}{W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Ishim of Devilry is turned face up, put a +1/+1 counter on it, then each opponent loses 2 life and you gain 2 life.

Menace, lifelink
Whenever Jonah of the Spellbane deals combat damage to a player, destroy target creature or planeswalker, then scry 1.

Sacrifice Kemono-no-Oni: Return target creature card from your graveyard to your hand.

Art of war — At the beginning of your end step, if Kurayami Butcher dealt damage to an opponent, you may destroy target creature that was dealt damage this turn.

Whenever another nontoken creature you control dies, you may exile it. If you do, create a 2/2 colorless Spirit creature token.

Menace
Whenever a nontoken creature you don't control dies, create a token that's a copy of that creature except it's a colorless Spirit. Exile it at the beginning of your next end step.

When Last-Thought Feeder dies, fateseal 2. (To fateseal 2, look at the top two cards of an opponent's library, then put any number of them on the bottom of that player's library and the rest on top in any order.)

When Lunar Defractor enters, each player discards a card.
Revive {5}{B}{B} ({5}{B}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Flying
{1}, Sacrifice a creature: Mahara Angel gets +1/+1 until end of turn.

Whenever Ming Fleet Privateer attacks, put a menace counter on target creature in its pack. (Two or more creatures you control with equal power are in a pack.)

Deathtouch
Respawn (When this creature dies, if it attacked this turn, return it to its owner's hand.)

Nameless Throng can't block.
{1}{B}, Exile an artifact or enchantment card from your graveyard: Return Nameless Throng from your graveyard to the battlefield.

Neckbreaker Viking gets +1/+0 and has menace 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.)

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Each player loses 1 life.
[Lore III] Create a 1/1 black Harpy creature token with flying.