msem-instigator

Create an X/X green Mutant creature token.
Draw a card.

Target creature you control explores. When it does, it deals damage equal to its power to target creature or planeswalker. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then you may put that card in your graveyard.)

Enchant opponent
Whenever enchanted player draws a card or casts a spell, put a foreshadow counter on Thalassophobia.
Remove eight foreshadow counters from Thalassophobia and sacrifice it: Create an 8/8 blue Kraken creature token.

First strike
Each other nontoken creature you control enters with an additional +1/+1 counter on it.

Whenever one or more cards leave your graveyard, put a soul counter on this creature.
This creature gets +1/+1 for each soul counter on it.
{1}{W}, Exile a creature card from your graveyard: This creature gains indestructible until end of turn. Tap it.

Bulwark — If you control a creature with toughness 4 or greater, each creature you control assigns combat damage equal to its toughness rather than its power this turn.
Creatures you control get +0/+2 until end of turn.

Flying
Other Vampire creatures you control get +1/+0 and have menace.

Heroic — Whenever you cast a spell that targets Thassa's Shoreguards, tap target creature an opponent controls. It doesn't untap during its controller's next untap step.
Whenever Thassa's Shoreguards deals combat damage to a player, draw a card.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Audition for black. (Create a 1/1 Construct Actor creature token, a Cleric Role giving 2/2 and lifelink, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)
III — Until end of turn, if a creature you don't control would die, instead exile it and that creature's controller loses 2 life.
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I — Exile target creature an opponent controls until The Banishment of Seh'a leaves the battlefield.
II — Exile up to three cards from target opponent's graveyard.
III — You gain life equal to the number of cards in exile.

Enchant creature
Enchanted creature has base power and toughness 1/1, and its activated abilities can't be activated.

Whenever The Ever-Pestilent deals combat damage to a player, that player discards a card at random.

Attacking creatures you control have trample.
Whenever a creature you control attacks, you may remove any number of +1/+1 counters from that creature. If you do, it gets +2/+2 until end of turn for each counter removed this way.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever the second card is put into your graveyard from anywhere each turn, add a quest counter.
1, 2 — You may sacrifice a creature. When you do, you may return target creature card from your graveyard to your hand.
3 — Destroy target nonland permanent an opponent controls.

(Add a quest counter as this enters. Sacrifice after 3.)
At the beginning of your end step, if you have more cards in hand than an opponent, add a quest counter.
1, 2 — Target opponent exiles the top card of their library. You may play that card for as long as it remains exiled. (You still pay its costs.)
3 — Create three Treasure tokens.

If a red source you control would deal damage, it deals that much damage plus 1 instead.
I, II — Exile the top card of your library. If it's red or a Mountain, you may play that card this turn.
III — Return target red instant or sorcery card from your graveyard to your hand.

(Add a quest counter as this enters. Sacrifice after 3.)
Whenever you draw your second card each turn, add a quest counter.
1, 2 — Scry 3.
3 — Create a blue and green enchantment token named The Heart with “Whenever you tap a land for mana, add one mana of any color.”

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Audition for green. (Create a 1/1 Construct Actor creature token, a Scout Role giving 2/3 and vigilance, or a Warrior Role giving 3/2 and trample. Roles replace older ones.)
III — Creatures you control get +1/+0 and gain trample until end of turn.
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(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Return target creature card from your graveyard to your hand.
II — Return target instant or sorcery card from your graveyard to your hand.
III — At the beginning of the next end step, create an X/X black Horror creature token, where X is the number of spells you cast this turn.

When The Marrow Lord enters, search your library for a card with arise, put that card into your graveyard, then shuffle.
Whenever you activate an ability of a card in your graveyard or a creature you control enters from a graveyard, this creature deals 1 damage to any target.

Each planeswalker you control is an Okus in addition to its other types.
[–1]: Search your library for a planeswalker card or an Aura card with enchant planeswalker, reveal it, and put it into your hand, then shuffle.
The Paragon of Haberdashery can be your commander. If it is, it's all colors.

Creatures you control get +1/+1 until end of turn.
Showcase {2}{W}{W} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

The Pillaging of Kaneh deals X damage to each creature and each planeswalker, where X is the number of Satrapies you control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Put a prowess counter on target creature you control. That creature deals 2 damage to each opponent.
II — Scry 3.
III — Until end of turn, if you casting an instant or sorcery spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Whenever The Pursuit of Science enters or a nontoken creature you control dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)
Clues you control have “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”