msem-instigator

At the beginning of each player's end step, that player chooses from among nonland permanents they control an artifact, a creature, an enchantment, and a planeswalker, then sacrifices the rest.

Deathtouch, lifelink
At the beginning of combat on your turn, for each creature your opponents control, you may tap an untapped creature you control. If you do, those creatures fight each other.

(Add a quest counter as this enters. Sacrifice after 3.)
At the beginning of your end step, if you cast two or more spells this turn, add a quest counter.
1, 2 — The Symphony of Leafdown deals 2 damage to any target. Draw a card.
3 — Until the end of your next turn, instant and sorcery spells you cast cost {1} less to cast.
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When The Third Breach enters the battlefield, discard your hand, then draw seven cards.
Creatures you control get +3/+3, have haste, and are Horrors in addition to their other types.
At the beginning of each end step, sacrifice each creature you control.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Distribute a trample counter, a vigilance counter and a +1/+1 counter among one, two, or three creatures you control.
III — Choose another permanent you control. For each counter on it, you may move that counter onto a permanent you control.​

Defender
Your maximum hand size is thirteen.
{T}: If you have fewer than thirteen cards in hand, draw cards equal to the difference. Activate only as a sorcery.

Permanent cards in your graveyard have The Undercity Amalgam's Adventure.
Once during each of your turns, you may cast an Adventure spell from your graveyard.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
Whenever you cast a spell from anywhere other than your hand, remove a lore counter from The Unhinging Project.
I — The Unhinging Project deals 2 damage to any target. You gain 2 life.
II — Discard your hand. Surveil 3.

The Unshakable Kian enters the battlefield with three wish counters on him.
Remove a wish counter from Kian: Choose one. Activate only as a sorcery and only once each turn.
• Kian gains hexproof and trample until your next turn.
• Tap up to three target nonland permanents and put a stun counter on each of them.
• If you have fewer than four cards in hand, draw cards equal to the difference.

The Urchin King's power and toughness are each equal to the number of cards in all graveyards.
Sacrifice a creature: The Urchin King gains lifelink and indestructible until end of turn.

Whenever you sacrifice a Clue, you lose life equal to the number of Clues you control, then investigate twice. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

[0]: Creatures you control gain haste until end of turn. Whenever a creature attacks this turn, put a loyalty counter on The Warrior Within.
[–1]: Exile the bottom two cards of your library. You may play one of them this turn.
[–6]: Untap each creature that attacked this turn. After this main phase, there is an additional combat phase.

Whenever The Wicker Lord or another Scarecrow enters the battlefield under your control, create a 1/1 black Bird creature token with flying for each Scarecrow you control.
{4}, Sacrifice a Scarecrow: Return target artifact card from your graveyard to the battlefield.

Whenever The Winged Steed attacks, create a 4/4 red Dragon creature token with flying that's tapped and attacking. Exile that token at end of combat.
Crew 2 (Tap any number of creatures you control with total power 2 or greater: This Vehicle becomes an artifact creature until end of turn.)

[+2]: The Witch Queens deal 2 damage to each of up to two targets.
[–3]: Gain control of target land and untap it.
[–9]: Each player discards their hand, then draws up to seven cards. The Witch Queens deal damage to each opponent equal to twice the number of cards that player has drawn this turn.

(As this Discovery enters and after your draw step, add a progress counter. Stop after you've discovered.)
I, II — Look at the top five cards of your library. Put up to one creature card with mana value 2 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Discovery — At the beginning of combat on your turn, tap target creature an opponent controls.

Enspirit (As you cast this spell, you may exile a nonenchantment creature you control until this leaves the battlefield or fails to resolve. Reduce this spell's cost by the exiled card's mana value.)
At the beginning of your upkeep, create a token that's a copy of the enspirited card. It gains haste until end of turn. Exile it at the beginning of the next end step.

Vanishing 3 (This permanent enters the battlefield with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a time counter is removed from Thespian's Finale, create a token that's a copy of target creature. Sacrifice that token at the beginning of your next upkeep.

Rhapsody {4}{U}{U} (Pay {4}{U}{U} to cast this as a 4/4, or as a sorcery to make it become a 4/4.)
Whenever you draw a card, any number of target players mill two cards.
Whenever This Is Not Our Fate deals combat damage to a player, for each player, you may cast an instant or sorcery card from that player's graveyard without paying its mana cost.

Other creatures have haste and attack each combat if able.
Nonland cards in your hand have paranoia {4}. (The owner of a card with paranoia {4} may cast it from their hand for {4} when a permanent they control leaves the battlefield.)

Other untapped creatures have hexproof.
Whenever a creature attacks you, put a +1/+1 counter on a creature you control.

(Choose only one work as a sorcery to add its ability.)
When Those Lost to the Waves enters the battlefield, search your library for an artifact card with mana value 3 or less, reveal it, put it into your hand, then shuffle.
{1}{W}: Fight the Current
Equipped creatures you control get +1/+1.
{3}{U}: Soul of the Sea
At the beginning of combat on your turn, you may have target noncreature artifact become a 3/3 artifact creature until end of turn.

When Thought Paradigm enters the battlefield, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
Whenever you cast a sorcery spell, target player mills three cards.

Whenever you draw a card, you may have target opponent exile the top card of their library face down.
You may look at and play cards exiled with Thought Siphon, and you may spend blue mana as though it were mana of any color to cast them.

Enchant creature
Enchanted creature gets +3/+1.