msem-instigator

Each opponent sacrifices a creature. For each creature sacrificed this way, create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Target creature gains lifelink or winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)
Put the bottom card of your library into your hand.

All creatures get -1/-1 until end of turn.
If ten or more cards are in your graveyard, creatures your opponents control get an additional -1/-1 until end of turn.

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

Target creature gets -6/-6 until end of turn.
Create a black enchantment token named Blight with “At the beginning of your upkeep, you lose 1 life.”

Choose one—
• Each opponent sacrifices a creature.
• Each opponent discards two cards.

Enchant creature
Enchanted creature gets +1/+0 for each card type among cards in your graveyard and has menace.
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards. You gain 2 life.

Search your library for a card, put that card into your hand, then shuffle.
Whenever you cast a spell with mana value 5 or greater, you may cast Words of Eternity from your graveyard without paying its mana cost. If you do, exile it instead of putting it into your graveyard as it resolves.

Destroy target creature or planeswalker, then exile its controller's graveyard.

Legacy (You may play this side of this card only from your graveyard. Exile it if it would be put into a graveyard or not resolve.)
Each opponent sacrifices a creature for each spite counter they have. If they didn't sacrifice any creatures this way, they discard that many cards instead.

When Writhing Gateway enters, you may discard a card. If you do, create a 5/3 black Horror creature token.
{1}{B}{B}, Discard a card: Create a 5/3 black Horror creature token.

Whenever you activate a loyalty ability of Xanigan, the Darkened Cloud, you get an emblem with exalted.
[+2]: Xanigan deals 2 damage to up to one target and you gain 2 life.
[–3]: You draw three cards and you lose 3 life.
[–7]: Xanigan becomes a 7/7 Demon creature with flying and indestructible that's still a planeswalker. Prevent all combat damage that would be dealt to her.

(Choose only one work as a sorcery to add its ability.)
When Xie'e Amphitheatre enters, search your library for a card and exile it face down, then shuffle. You may cast that card on any turn you sacrificed a permanent.
{B}: Intro: Together
At the beginning of your upkeep, you lose 1 life and create a 0/1 black Cultist creature token with “{1}{B}{B}, Sacrifice three Cultists: Create a 5/5 black Demon creature token.”
{2}{B}: Finale: Alone
Whenever a Demon you control enters, each opponent loses life equal to its power and you gain that much life.

Demon spells you cast cost {2} less to cast and an additional 2 life to cast.
Whenever you cast a Demon spell, create a 0/1 black Cultist creature token with “{1}{B}{B}, Sacrifice three Cultists: Create a 5/5 black Demon creature token.”

Choose two —
• Shuffle up to two target cards from graveyards into their owners' libraries.
• Create a 1/1 black Skeleton creature token. You lose 1 life.
• Sacrifice a permanent. Draw a card.

Foretell {4}{R}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Each player sacrifices four lands. A Kingdom Burns deals 4 damage to each creature and each planeswalker.

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
Abandon Life and Hope deals 5 damage to target creature or planeswalker.

As an additional cost to cast this spell, discard a card.
Draw two cards. Forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

As an additional cost to cast this spell, sacrifice an artifact or creature.
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Abrupt Explosion deals X damage to any target.
Metamorph {X}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up and cast it at any time for its metamorph cost.)

Destroy target artifact or land.

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (If you exert it, it will still untap for other players.)

Target instant or sorcery spell gains “This spell deals 4 damage to you.”