msem-instigator

Defender (This creature can't attack.)
Whenever you cast a spell during an opponent's turn, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

Flash
When Qililia's Scavenger enters, look at the top six cards of your library. You may put a Merfolk card with lesser mana value from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
Other Merfolk you control get +1/+1.

Scry 2, then draw a card.
If you control a legendary permanent, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

When Rune-Scribe's Apprentice enters, target player mills four cards.

This spell can't be countered.
Draw a card.
Reprise {2}{U} (As you cast an instant or sorcery spell, you may exile one card with reprise from your graveyard and pay its reprise cost. If you do, add its effects to that spell.)

You may reveal the second card you draw each turn as you draw it. When you do, create a 2/2 blue Avatar Wizard creature token with prowess if it's a creature card. If it's a land card, create a Treasure token. If it's a noncreature, nonland card, Steward of Second Sphere can't be blocked this turn.
{3}{W/U}{W/U}: Scry 2.

Synchronous Battle Armor and equipped creature get +1/+1 for each artifact you control.
Whenever equipped creature attacks, tap up to three target creatures.
Reconfigure {3}{U}{U} ({3}{U}{U}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

When Temur Falconer enters, create a 1/1 blue Bird creature token with flying.
Whenever a creature you control with flying deals combat damage to a player or planeswalker, put a +1/+1 counter on Temur Falconer.

Counter up to one target spell unless its controller pays {2}. Until end of turn, you may cast spells as though they had flash.

When Hail to the Queen enters, each player sacrifices a creature.
Whenever a nontoken creature you control dies, you may pay its mana cost. If you do, create a token that's a copy of it.

Flying
Whenever an opponent discards a card, you may exile it. If you do, create a 1/1 black Bird creature token with flying and “This creature can't block.”
{B}, Sacrifice three Birds: You may cast a card exiled with Krahen, Dusk's Call without paying its mana cost.

(Transcend as a sorcery to gain that type and a +1/+1 counter.)
Lifelink
Demon spells you cast cost {B} less to cast and an additional 2 life to cast.
{3}{B/R}{B/R}: Demon
Discard your hand. Draw a number of cards equal to the greatest power among Demons you control.
{5}{U/B}{U/B}: Noble
Gain control of target creature. You lose life equal to its mana value.

When Maven of Fear enters, mill two cards.
Maven of Fear gets +2/+1 and has menace as long as six or more cards are in your graveyard.

Poisonous 1 (Whenever this creature deals combat damage to a player, that player gets a poison counter. A player with ten or more poison counters loses the game.)
At the beginning of your upkeep, if an opponent is poisoned, you draw a card, you lose 1 life, and you get a poison counter.

Whenever an opponent discards a card, exile it. You may cast that card as long for as it remains exiled, and you may spend black mana as though it were mana of any color to cast that spell.

Whenever you cast a black spell, choose up to X, where X is the number of black mana symbols in that spell's mana cost —
• Target player loses 1 life and you gain 1 life.
• Put a -1/-1 counter on target creature.
• You draw a card and you lose 3 life.
• Exile target card in a graveyard.

Choose one —
• Target creature gets +1/+1 and gains lifelink until end of turn.
• Target creature gets -2/-2 until end of turn.
• Scry 1, then draw a card.

When Treacherous Warden enters, search your library for a card, put into your graveyard, then shuffle.
Whenever a creature enters from your graveyard, each opponent loses 2 life and you gain 2 life.

Flying
If Warden of Distortion would die, you may exile a creature card from your graveyard. If you do, Warden of Distortion becomes a copy of that creature, except it's a 4/4 Nightmare Dragon and it has flying and this ability. It gains indestructible until end of turn.

This spell costs {2} less to cast if it targets a creature or planeswalker card with mana value 3 or less.
Return target creature or planeswalker card from your graveyard to the battlefield.

Whenever Yri, the Daring Blade and exactly one other creature attack, Yri and that creature can't be blocked by creatures with mana value 3 or less this turn.

This spell can't be countered.
When Auros enters, it deals damage to any target equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)
{R}, Sacrifice Auros, Discard your hand: Draw three cards.

Whenever Borsuppa Roughrider attacks, create a colorless Desert land token named Scoured Path with “{T}: Add {R}.” Sacrifice that token at the beginning of the next end step.

Ferocious — At the beginning of your first main phase, if you control a creature with power 4 or greater, add {R}.

Prowess
When Cramming Student enters, conjure ten cards named Fatigue and shuffle them into your library. (They're colorless sorceries that cost {2} and have “Draw a card.”)
Instant and sorcery spells you cast cost {1} less to cast.