msem-instigator

This spell costs {1} less to cast for each time you catalyzed this turn.
Counter target spell unless its controller pays {X}.

Whenever Deluge Crab perseveres, target opponent mills three cards. (A creature perseveres when it survives damage.)

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Each creature you control with a counter on it has ward {2}. (If a creature has multiple instances of ward, each triggers separately.)

Creatures you don't control get -1/-0 as long as their controller is cursed.

When Delugic Surger enters, if you control another Elemental, return target instant or sorcery card from your graveyard to your hand.

Delusional Noble enters with a -1/-1 counter on it.

When Delusive Shadows enters, each opponent loses life equal to the number of cards that player owns in exile.

Repeat the following process X times. Reveal the top two cards of your library. Put one of them into your hand and the other into your graveyard.

(As this Saga enters and after your draw step, ad a lore counter. Sacrifice after III.)
I, II — Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
III — You may sacrifice any number of artifacts. If you do, draw that many cards.

Up to three target creatures can't block this turn.
Menagerie — If there are five or more creature types among creatures you control, exile the top three cards of your library. You may play one of those cards until the end of your next turn.

At the beginning of your upkeep, choose a creature. Its controller may sacrifice it. If that player doesn't, you gain life equal to its power.

Target creature gets +5/+5 until end of turn.
Fabled {4}{G} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

At the beginning of each player's end step, that player sacrifices a permanent.

Whenever an opponent casts a spell, harmonize. (Trigger up to one harmony of a permanent you control.)
Harmony — Spells your opponents cast cost an additional 2 life to cast until your next turn.

When Demented Brainiac enters and at the beginning of your upkeep, each opponent mills two cards.
{U}, Sacrifice Demented Brainiac: Exile each opponent's graveyard. Until end of turn, you may cast instant and sorcery spells exiled this way, and you may spend mana as though it were mana of any color to cast them.

Trample
At the beginning of your upkeep, sacrifice another creature. If you do, put X +1/+1 counters on Demented Host, where X is that creature's power.

Target player discards two cards.
Cycling {2}{B} ({2}{B}, Discard this card: Draw a card.)
When you cycle Dementia's Clutch, target player discards a card.

Destroy target artifact or land.

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
When Demolitionist Deviser dies, it deals damage equal to its power to any target.

This spell costs {2} less to cast for each creature that died this turn.
Flying, trample

{1}{B}, Sacrifice another creature: Draw a card and 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.”)
{2}{B}, Sacrifice three Idols: Return Demon of Hubris from your graveyard to the battlefield. Activate only as a sorcery.

At the beginning of your end step, if you've sacrificed three or more permanents this turn, return Demon of Necessary Evil from your graveyard to the battlefield.

Whenever a player searches their library, that player can't untap more than two permanents during their next untap step.

Create a 4/4 black Demon creature token with flying. You lose 3 life for each Demon you control.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

When Demonqueller Mage enters, gain control of target creature with power 2 or less until Demonqueller Mage leaves the battlefield.