msem-instigator

First strike
Noncreature spells cost {1} more to cast as long as their controller is horrific. (A player is horrific as long as they've sacrificed a permanent or discarded a card this turn.)

If another creature you control would die, exile it instead.
When John Furo, the Unfortunate dies, until your next end step, you may play cards exiled with John Furo.

Whenever you cast a spell from exile, copy that spell. You may choose new targets for the copy.
{B}, Discard a card: When you cast your next spell from your hand this turn, it gains rerun. Activate this ability only once each turn. (Exile it as it resolves if you cast it from your hand. Whenever a creature you control dies, you may cast that card from exile without paying its mana cost.)

Whenever Morbid Mimic enters the battlefield or attacks, exile up to one target creature card from a graveyard.
Morbid Mimic has all activated abilities of cards exiled with it.

Whenever you tap a land for mana, add one mana of any type that land produced.
Whenever you cast a spell with mana value greater than the number of lands you control, sacrifice a land.

You may have Raging Reflection enter the battlefield as a copy of any creature on the battlefield, except it has “When this creature enters the battlefield, it fights another target creature that shares a name with it.”

Ravenous Attraction enters the battlefield with a +1/+1 counter on it.
Whenever a creature you control dies, double the number of each kind of counter on Ravenous Attraction.

This spell costs {2} less to cast for each creature that died this turn.
Each player exiles all creature cards from their graveyard, then sacrifices each creature they control, then puts all creature cards they own exiled this way onto the battlefield. Exile Sea of Corpses.

Trample
When The Shepherd of Nowhere enters the battlefield, each player sacrifices each other nontoken creature they control.
Whenever another nontoken creature you control dies, create a token that's a copy of that creature.

Menace
Discard a creature card or sacrifice a creature or exile a creature card from your graveyard: Put a +1/+1 counter on Starving Stalker. Activate only once each turn.

Enshrouded Village enters the battlefield tapped.
{T}: Add {G}.
{1}{G}{G}: Until end of turn, Enshrouded Village becomes a 4/4 Human creature with trample. Activate only if you're horrific.

Hellfire Caverns enters the battlefield tapped.
{T}: Add {R}.
{2}{R}: Until end of turn, Hellfire Caverns becomes a 3/3 Devil creature with menace. Activate only if you're horrific.

Lost Station enters the battlefield tapped.
{T}: Add {U}.
{U}{U}: Until end of turn, Lost Station becomes a 2/2 Horror creature with “This creature can't be blocked.” Activate only if you're horrific.

Misty Churchyard enters the battlefield tapped.
{T}: Add {W}.
{1}{W}{W}: Until end of turn, Misty Churchyard becomes a 1/4 Cleric creature with “Whenever this creature is dealt damage, put that many +1/+1 counters on it.” Activate only if you're horrific.

Sunken Homestead enters the battlefield tapped.
{T}: Add {B}.
{2}{B}: Until end of turn, Sunken Homestead becomes a 2/2 Zombie creature with “When this creature dies, return it to the battlefield.” Activate only if you're horrific.

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

Sacrifice Amateur Auteur: Destroy target enchantment.

Creatures you control get +0/+1 and can attack as though they didn't have defender.
Whenever three or more creatures you control attack or block, each creature you control assigns combat damage equal to its toughness rather than its power this turn.

Whenever a permanent you control transforms, draw a card.

Target creature gets +2/+2 and gains flying and lifelink until end of turn.
Orchestrate {W} (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Whenever Distracting Performer becomes tapped, you may tap target creature.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
You can't lose the game and your opponents can't win the game.
I — Your life total becomes 1.
II — Double your life total.
III — Create an X/X white Avatar creature token with indestructible, where X is your life total.

Return target Actor or enchantment card from your graveyard to the battlefield.

Untap all creatures you control. They get +0/+2 until end of turn.

When Evigian Crusher enters the battlefield, untap all creatures you control.
Orchestrate {1}{W}{W} (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)