msem-instigator

When Hashiro's Vanguard enters the battlefield, each player sacrifices a nontoken creature.

You may cast Heralds of Shikai from your graveyard as long as a creature an opponent controls died this turn.

When Keeper of Dark Shadows enters the battlefield, if it's not a token, target opponent reveals their hand. You may choose a creature card from it. Create a token that's a copy of that card, except it's a colorless Spirit.

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

Equipped creature gets +2/+2.
Whenever equipped creature attacks, you may return target creature card with mana value 2 or less from your graveyard to the battlefield.
Equip {2}

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.

Whenever you gain life for the first time each turn, each opponent loses 2 life.

Pay 3 life: Put a +1/+1 counter on target creature.

When Sasori Nightrunner enters the battlefield, create a 2/2 colorless Spirit creature token.
Whenever a colorless creature you control dies, each opponent loses 1 life.

Destroy target creature. If an opponent lost life this turn, that creature's controller mills five cards.

Menace
Art of war — At the beginning of your end step, if Shikai Hunters dealt damage to an opponent this turn, put a +1/+1 counter on it.

Shikai Revenant enters the battlefield tapped.
At the beginning of your end step, if an opponent lost life this turn, you may return Shikai Revenant from your graveyard to your hand.

Partner with Kasoha, Keeper of Truths (When this creature enters the battlefield, target player may put Kasoha into their hand from their library, then shuffle.)
Whenever Shizura, Keeper of Traditions or another legendary creature dies, target player draws two cards and loses 2 life.

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

Return target creature card from your graveyard to your hand.
Inscribe {3}{B} ({3}{B}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Whenever you cast an instant or sorcery spell, target creature gets +1/+1 until end of turn.

{T}, Sacrifice an Equipment: Return target Equipment card from your graveyard to the battlefield. Activate only as a sorcery.

Fires of Seishin deals 2 damage to any target.
Draw a card.

Cast this spell only before attackers are declared.
Target creature you control gets +X/+0 until end of turn and gains haste until end of turn, where X is its power. At the beginning of the next end step, sacrifice that creature if it attacked this turn.

When Ikari-no-Oni enters the battlefield, other creatures you control get +1/+0 until end of turn.

Destroy target nonbasic land.

Art of war — At the beginning of your end step, if Jaakuna Betrayer dealt damage to an opponent this turn, you may discard a card. If you do, draw a card.

When Jaakuna Bloodsworn enters the battlefield, any opponent may have it deal 3 damage to them. If a player does, sacrifice Jaakuna Bloodsworn.

Double strike
Art of war — At the beginning of your end step, if Jaakuna Tyrant dealt damage to an opponent this turn, put a +1/+1 counter on it.