msem-instigator

Sabotage — Whenever an opponent or permanent an opponent controls becomes the target of a spell you control, put a +1/+1 counter on Mirrorcast Battlemage.
Remove three +1/+1 counters from Mirrorcast Battlemage: Copy target instant or sorcery spell you control. You may choose new targets for the copy. Activate only once each turn.

Prevent all combat damage that would be dealt to creatures this turn. Creatures that attacked you this turn don't untap during their controller's next untap step.

Siphon (Each -1/-1 counter you put on your creatures up to their remaining toughness while casting this pays for {1}.)
Create a token that's a copy of target creature you control, except it enters with an additional -1/-1 counter on it.

Enchant creature
Enchanted creature has distorted. (This creature can be blocked by tapped creatures but not untapped creatures.)
{1}{W}: Tap enchanted creature.

Flying
Whenever you cast an instant or sorcery spell, put a +1/+1 counter on Mirrorfuse Angel, then copy that spell for each +1/+1 counter on Mirrorfuse Angel. You may choose new targets for the copies.

Whenever a player casts an instant or sorcery spell that targets only one target or activates an ability that targets only one target, copy that spell or ability for each other target it could target. Each copy targets a different one of those targets. (A spell or ability can't target itself.)

When you cast this spell, copy it for each Reflection creature you control. You may choose new targets for the copies.
Mirrorstorm deals 1 damage to any target and you gain 1 life.

Flying, ward {2}
At the beginning of your upkeep, if Mirrorwing Commander is embattled, create a token that's a copy of it. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Counter target spell.

Flash
Whenever Mischievous Capuchin or another Monk you control enters, tap target creature you don't control. If it was already tapped, it doesn't untap during its controller's next untap step.

Flash (You may cast this spell any time you could cast an instant.)
Flying (This creature can't be blocked except by creatures with flying or reach.)

[+1]: Scry 3.
[–2]: Choose a card name, then mill a card. If that card has the chosen name, you draw three cards. Otherwise, you draw a card.
[–6]: You get an emblem with “Play with the top card of your library revealed” and “You may play the top card of your library.”

Flash
Flying
When Mischievous Sprite enters,you may tap or untap target permanent.

Create a 1/1 blue Illusion creature token with “This gets +1/+1 for each other Illusion you control.”
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Put target creature into its owner's library third from the top.

[+2]: Target player exiles a card from their hand at random. Until the end of that player's next turn, they may play that card.
[0]: Gain control of target creature or planeswalker until end of turn. Tap it.
[–9]: Take an extra turn after this one. During that turn, you control all opponents.

[+2]: Create a Vial token. (It's an artifact with “1, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)
[–3]: Sacrifice another nonland permanent. If you do, destroy target nonland permanent.
[–9]: You get an emblem with “At the beginning of your end step, create Fallen One, a legendary 6/6 black Faerie Angel Avatar creature token with flying.”

Other creatures you control get +2/+0 and have menace.
Whenever another creature you control dies, if it wasn't sacrificed, sacrifice a creature.

Flash (You may cast this spell any time you could cast an instant.)
When Mist Lurker enters, tap all creatures you don't control.

Hexproof
Mist-Valley Ancient enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

{1}{R}, Discard a card: Draw a card. Mist-Valley Minotaurs gets +2/+0 until end of turn.

Vigilance
Ignore all effects that would prevent Mistbreaker from attacking or blocking. (If an effect says it “can't” attack or block, it still can. This ability doesn't let it attack or block if it's tapped or attack if it has summoning sickness.)

You may play an additional land on each of your turns.
{4}{U}{U}: Transform Misthollow Rites. Activate only as a sorcery.

Other Spirits you control get +1/+1.
Whenever Mistmourner or another Spirit you control enters, you may draw a card. If you do, discard a card.

Mistwake Hydra enters with X +1/+1 counters on it.
Creatures with power less than Mistwake Hydra's power can't block it.