msem-instigator

Thalassic Borough enters tapped unless you have 15 or less life.
{T}: Add {U} or {B}.

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.

When Thallid Cultivator dies, mill four cards. Return a creature card milled this way to your hand.

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

Whenever you draw a card except for the first one you draw in each of your draw steps, each opponent loses 1 life.

Bulwark — When Tharanos' Legion enters, draw a card for each creature you control with toughness 4 or greater.

Lifelink
Bulwark — Whenever Tharanos' Sentinel attacks, if you control a creature with toughness 4 or greater, untap 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
At the beginning of combat on your turn, gain control of up to one target creature an opponent controls. If you do, untap it, and it gets +4/+4 and gains flying and haste until end of turn. Sacrifice it at the beginning of the next end step.

Search your library for a card and put that card into your hand. Then shuffle.
When Tharyen's Machinations is engorged, you may search your library for a card with the same mana value as the permanent that engorged it, reveal it, put it into your hand, then shuffle.

Destroy target creature. Then if there are ten or more cards in your graveyard, return target creature card from your graveyard to your hand.

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

Flying, lifelink
Whenever you gain life, each opponent loses 1 life.
{4}{B}{B}: Create a 1/1 black Vampire creature token with lifelink for each nontoken creature that died this turn.

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.

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.

Reconstruct {4}{B}{B}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)
Destroy all creatures. If The Afterlife Takes Its Due was reconstructed, create an X/X black Zombie Horror creature token, where X is the number of creature cards that have been put into graveyards this turn.

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

At the beginning of the next end step, create X 1/1 white Spirit creature tokens with flying, where X is the number of creatures that died this turn.
Reconstruct {2}{W}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)