msem-instigator

When Herald of Teardrops enters, choose one. If you control another Elemental, you may choose both instead.
• Create a 1/1 blue Elemental creature token with flying.
• Put a +1/+1 counter on each of up to two creatures.

Non-Human creatures you control get +1/+0.

Whenever you draw a card, target player mills two cards.
Whenever you cast a blue spell, scry 1, then you may reveal the top card of your library. If it's an instant or sorcery card, draw a card.

Vigilance
Each nontoken creature you control gets +1/+1 for each other creature on the battlefield with the same name as it.

When Journey to Elrayin enters, journey, then choose a creature card name. (To journey, exile the top card of your library face up. Whenever a creature you control deals combat damage to a player, put a journeyed card you own into your hand.)
Whenever a creature you control with the chosen name deals combat damage to a player, journey.

Choose two —
• Target player creates two 2/2 white Knight creature tokens with vigilance.
• Destroy target creature with power 4 or greater.
• Target player gains hexproof until end of turn.
• Return target nonland permanent you don't control to its owner's hand.

[+1]: Create three 1/1 white Warrior creature tokens. They gain haste.
[0]: Until end of turn, each creature and planeswalker you control becomes a 3/3 Warrior creature and gains indestructible. (Permanents don't lose loyalty while they're not a planeswalker.)
[–2]: Choose tapped or untapped. Seto San deals 3 damage to each creature with the chosen attribute.

Trample, haste
Crew—Tap three untapped artifacts and/or creatures you control.

{T}: Tap target creature. Activate only if Wizened Veteran is embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

You may activate loyalty abilities of Xirix, the Usurper during extra turns any time you could cast an instant.
[+1]: Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
[–2]: Destroy each nonland, non-Xirix permanent with the greatest mana value among non-Xirix permanents on the battlefield.
[–6]: Put target permanent card from a graveyard onto the battlefield under your control.

{2/W}{2/W}: Shrapnel Golem deals 3 damage to target creature blocking it.

Enchant creature
Enchanted creature gets +1/+1 for each other creature on the battlefield that shares a creature type with it.

Whenever an Aura you control enters, untap Fuming Lawmaker.
{1}, {T}: For each opponent, Fuming Lawmaker deals 1 damage to that player or a planeswalker they control. Scry 1.

Destroy target artifact or enchantment. Purge. (Exile two cards that share a type from graveyards. If you do, draw a card.)

Whenever The First Idol attacks, 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.”)
Sacrifice three Idols: Return The First Idol from your graveyard your hand.

When Indomitable Duo enters, choose up to two creature card names.
Whenever Indomitable Duo attacks, put a +1/+1 counter on each creature you control with a name chosen by Indomitable Duo.

Vision (Whenever this or another creature you control enters, reveal the top card of your library. Then you may put that card into your graveyard.)
Whenever Blind Soulcaller envisions an instant or sorcery card, you may tap target permanent.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — You may exile target nonland permanent. If you do, you lose 3 life.
III — Create a 7/7 white, black, and green Horror Knight creature token with trample and “Whenever this creature is dealt damage, you lose that much life.”
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Enchant creature
As long as enchanted creature has toughness 3 or less, it can't attack or block.

Enchant creature
Enchanted creature gets -3/-3.

Menace
Swampcycling {1}, forestcycling {1} ({1}, Discard this card: Search your libary for a Swamp or Forest card, reveal it, put it into your hand, then shuffle.)

As Ocean Monastery enters, you may pay 2 life. If you don't, Ocean Monastery enters tapped.
{T}, Sacrifice Ocean Monastery: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Enchant permanent
Enchanted permanent is a land with “{T}: Add {G}{W}{U}” and loses all other card types and abilities.
{1}, Discard Song of Shoals: Add one mana of any color. Scry 1.

Gain control of target creature until end of turn. Untap that creature. It gains haste and defiance until end of turn. (Whenever that creature takes damage, if it survives and wasn't defiant, put a +1/+1 counter on it and it becomes defiant.)

Whenever you cast an instant or sorcery spell, Kederekt Deepdweller gains your choice of indestructible, lifelink, or menace until end of turn.
Whenever Kederekt Deepdweller deals combat damage to a player, you draw a card and that player discards a card.