msem-instigator

Enchant creature you control
When Thassa's Benefaction enters, scry 2.
Enchanted creature gets +1/+0 and has flying.

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.

{5}{U}{U}: Thassa's Tidebringer can't be blocked this turn. This ability costs {1} less to activate for each creature you control with a counter on it.

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of each combat, you may tap or untap another target nonland permanent.
{2}{U}: Create a 1/1 blue Merfolk Rogue creature token with “{T}: Draw a card, then discard a card.”

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
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.)
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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Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Thawing Valley enters tapped unless you control a basic land.
{T}: Add {G} or {U}.

Your opponents play with their hands revealed.
Whenever you cast a spell with the same name as a card in an opponent's hand, draw two cards.

{T}: Add {C}.
{5}, {T}, Sacrifice The Aetherite Saloon: Each player discards their hand and draws seven cards.

As this permanent transforms into The All-Consuming Swarm, counters on her become loyalty counters instead.
[+2]: Create three 1/1 black and green Insect creature tokens with flying.
[–3]: For each permanent type, each opponent sacrifices a permanent of that type.

Once each turn, if a triggered ability of another legendary permanent you control would trigger, you may have it trigger an additional time.

Menace
When The Anguilahydra enters, draw X cards and put X +1/+1 counters on The Anguilahydra, where X is the number of enchantments you control.

Haste, prowess
Whenever you cast a noncreature spell, journey. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to an opponent, put a journeyed card you own into your hand.)

Hexproof, crew 6 (Tap any number of creatures you control with total power 6 or greater: This Vehicle becomes an artifact creature until end of turn.)
Whenever The Ark Project deals combat damage to an opponent or planeswalker, gain control of target creature until The Ark Project leaves the battlefield.
Whenever The Ark Project blocks a creature, gain control of that creature.

(Choose only one work as a sorcery to add its ability.)
When The Art of War enters, if a source you control would deal damage this turn, it deals double that damage instead.
{2}{R}{R}: Laying Plans
Whenever you attack for the first time each turn, untap each creature you control. After this phase, there is an additional combat phase.
{2}{R}{R}: Waging War
Whenever a creature you control attacks, create a token that's a copy of it that's tapped and attacking, except the token isn't legendary. Exile those tokens at end of combat.

{T}, Pay 1 life: Add {U}.
{4}{U}{U}{U}, Exile The Aurora's Heart from your hand: Target player draws seven cards.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Put all creature cards from your graveyard onto the battlefield.
II — Creatures you control gain lifelink until end of turn.
III — Destroy all creatures.

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.

Whenever a creature you control dies, put a unity counter on The Blacksmith's Banner.
Creatures you control have vigilance and get +1/+1 for each unity counter on The Blacksmith's Banner.

[+1]: Remove up to one loyalty counter from each other planeswalker. Up to one target player loses 1 life for each counter removed this way.
[–1]: For each other player and permanent, remove a counter from it or give it another counter of a kind that permanent or player already has.
[–4]: Put target nonland permanent on the bottom of its owner's library.

If you would look at or reveal one or more cards of a library, you may first search that library for that many cards, shuffle that library, then put those cards on top of it in any order.

Flying, haste
Whenever The Branded Usurper attacks, it deals 2 damage to any target.
If you would lose the game, instead exile The Branded Usurper. Your life total becomes 0. Until an opponent's next turn, you can't lose the game and you can't gain life. Take an extra turn after this one.

Menace
Whenever a creature dies, you gain life equal to its power.
Reappropriate: Put a +1/+1 counter on The Cannibals of Kallio Hill, then lose life equal to its power. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)

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

When The Clocktower Project enters, create a tapped colorless Powercell artifact token with “{T}: Add {C}.”
Tap seven untapped artifacts you control: Draw three cards.