msem-instigator

Search your library for a land card and put that card onto the battlefield tapped with a venom counter on it. It gains “Whenever this land is tapped for mana, you lose 1 life.” Then shuffle.

Target creature gets -2/-2 and is marked until end of turn.

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Poisonheart Undead enters, you draw a card and you lose 1 life.

When Poisonous Growth enters, create a 1/1 green Saproling creature token, then attach Poisonous Growth to it.
Equipped creature has deathtouch.
Equip {4}

Whenever a land enters under an opponent's control, that player loses 2 life and you gain 2 life.

Whenever Portal Inhibitor attacks, exile target nonland card from defending player's graveyard. Copy it. You may cast the copy. (You still pay its costs, including color. Copies of permanents enter as tokens.)

Target player sacrifices a creature. Fateseal 1. (To fateseal 1, look at the top card of an opponent's library, then you may put it on the bottom of that player's library.)

Return target artifact or creature card from your graveyard to your hand.
Draw a card.

You may put a card you own from outside the game into your hand. Add {B}{B}. You may cast only one more spell this turn. Exile Power From Beyond.

(Activate each submodule once as a sorcery. When this enters, activate one submodule for free.)
{B}{B}{B}: Ambitous
Search your library for a card, put it into your hand, then shuffle. You lose 3 life.
{B}{B}{B}: Ruthless
Destroy target creature or planeswalker.
{B}{B}{B}: Determined
Power Module gains “At the beginning of your upkeep, you draw a card and you lose 1 life.”

Vanishing 3
Whenever a time counter is removed from Prayers of Defiance, return target creature card from your graveyard to your hand.

Vanishing 3
Whenever a time counter is removed from Prayers of Judgement, each player loses 1 life and mills two cards.

Vanishing 3
Whenever a time counter is removed from Prayers of Release, you may put a -1/-1 counter on target creature.

Preacher of the Yenzu gets +2/+0 and has flying as long as you control a legendary creature.

Predatory Abomination has deathtouch and lifelink as long as you control another Horror.

You draw two cards and you lose 2 life.
Amass Soldiers 2. (Put two +1/+1 counters on an Army you control. It's also a Soldier. If you don't control one, create an 0/0 black Soldier Army creature token first.)

{2}, {T}, Sacrifice a creature: Each opponent loses 2 life. You gain life equal to the life lost this way.

Target creature you control gets +2/+0 and gains indestructible until end of turn. You lose 2 life.

Surveil 1, then draw a card. You lose 1 life.
Flashback—{B}, Sacrifice a creature. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Exile target creature, enchantment, or planeswalker. You lose life equal to its mana value.

Discard a card, then return up to two creature cards from your graveyard to your hand.

Choose two or four —
• Search your library for a Demon card, reveal it, put it into your hand, then shuffle. You lose life equal to its mana value.
• Sacrifice a creature. If you do, draw two cards.
• Each opponent loses 2 life and you gain 2 life.
• Conjure a card named Fatigue and put it on top of your library. (It's a colorless sorcery that costs {2} with “Draw a card.”)

Profane Emissary gets +2/+2 and has lifelink as long as you control a Demon.
If you would draw a card, you may instead search your library for a Demon card, reveal it, put it into your hand, then shuffle. You lose life equal to that card's mana value.

Flying, lifelink
Pay 5 life: Put target permanent card in a graveyard onto the battlefield under your control.

When Profaner of Souls enters, you may return target creature card with mana value 2 or less from your graveyard to the battlefield.
Revive {6}{B} ({6}{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.)