msem-instigator

Battalion — Whenever Callous Trainer and at least two other creatures attack, create a 1/1 white Warrior creature token that's tapped and attacking.

Enchant opponent
Whenever enchanted player is attacked, choose an attacking creature. Create a tapped and attacking token that's a copy of it. Exile the token at the beginning of the next end step.

When Lumen Cell enters, create a 1/1 white Human creature token, then put a +1/+1 counter on a creature you control.
{1}{W}: Search your library for a card named Lumen Cell, reveal it, put it into your hand, then shuffle.
{6}{W}{W}{W}: You win the game. Activate only if you control four or more permanents named Lumen Cell.

Once during each of your turns, you may cast a legendary creature or planeswalker spell from your graveyard.
Sacrifice Pallid Herald: Exile up to three target cards from graveyards.

Profane Emissary gets +2/+2 and has lifelink as long as you control a Demon.
If you would draw a card, you may instead search your library for a Demon card, reveal it, put it into your hand, then shuffle. You lose life equal to that card's mana value.

Hexproof
Whenever attackers are declared, the active player may pay {2} for each creature attacking you. Then you may have Bridge Kalak become an X/X Troll creature until end of turn, where X is the number of times that player didn't pay mana this way.

Whenever a creature you control dies, destroy target creature you don't control.

Counter target noncreature spell unless its controller pays {1}. If there are four or more counters among creatures you control, counter that spell instead.

Flying
When Rushwater Hunter enters, you may return target creature to its owner's hand.

Transcend (Activate as a sorcery to gain the next type and a +1/+1 counter.)
The first instant or sorcery spell you cast on each of your turns costs {U/R} (or {1}) less to cast.
{U}{R}: Angel — Put a flying counter and a prowess counter on Rahstahde.
{5}{U}{R}: Elder — Exile any number of instant and/or sorcery cards from your graveyard. For each card exiled this way, copy it. You may cast the copies without paying their mana costs.

Glacial Vista enters tapped.
{T}: Add {W} or {U}.
{1}, {T}: Add one mana of any color.

Enchant creature
Enchanted creature gets -X/-X, where X is 1 plus the number of counters on it.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II, III — Create a tapped colorless Powercell artifact token with “{T}: Add {C}.”
IV — Sacrifice three artifacts.
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You have no maximum hand size.
Whenever a player casts a spell, put a +1/+1 counter on Humar.
At the beginning of your upkeep, target player draws cards equal to Humar's power.

Flying, menace, haste
When Bloodfiend Ravager enters, it deals 2 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.
Evoke {1}{R} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Flash
When Hexfang Ascetic enters, return target spell to its owner's hand.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Counter target permanent spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.
3 | You gain life equal to its mana value.

Whenever you scry, put a +1/+1 counter on Shimmershell.

Inversion of Flesh deals 5 damage to each creature and each planeswalker, and 5 damage to each player with the highest life total or tied for highest life total among players.

You may pay {2}{B}{B} and tap an untapped Pirate you control rather than pay this spell's mana cost.
Target player draws three cards and loses 3 life.

As an additional cost to cast Scavenger's Skill, you may reappropriate. (To reappropriate, exile exactly two cards from your hand and/or graveyard.)
Scavenger's Skill deals 3 damage to target creature or planeswalker. When that permanent dies this turn, if Scavenger's Skill's additional cost was paid, draw a card.

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)

[+2]: Each opponent loses 2 life. Scry 2.
[–3]: Return target creature to its owner's hand. That player discards a card.
[–6]: You get an emblem with “Whenever a player discards a card, you may cast it without paying its mana cost.”

When Rei's Cultivator enters, create a green Aura enchantment token named Sowing Spring attached to target land. The token has enchant land, “Enchanted land's name is Flowering Expanse” and “Whenever enchanted land is tapped for mana, add one mana of any color.”

Target creature gets +2/+2 until end of turn. If it's an artifact creature, it gains indestructible until end of turn.