msem-instigator

Landfall — Whenever a land you control enters, target player loses 1 life and you gain 1 life.

Drown deals 2 damage to target creature. That creature can't block this turn.

This spell can't be countered.
Tap up to three target permanents.
Coalesce {9}{U}{U} (You may cast this from your graveyard for {9}{U}{U}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)
Opponents can't untap more than two permanents during their untap steps while Drown Amidst the Cosmos is on the battlefield.

When Drown in Apathy enters, exile target creature until Drown in Apathy leaves the battlefield. If a permanent would be returned to the battlefield this way, put it in its owner's hand instead.

Target player reveals their hand. You choose a nonland card from it. That player discards that card, then mills four cards.

All creatures get -2/-2 until end of turn. Scry 1.

{U}, Sacrifice a creature: Discard a card, then draw a card.

Whenever you cast a blue spell, you may cast creature spells this turn as though they had flash.
Whenever you cast a black spell, put up to one target card from your graveyard on top of your library.

When Drownyard Scavenger enters, each player may return an instant or sorcery card from their graveyard to their hand.

Prevent all combat damage that would be dealt to you this turn. Populate. (Create a token that's a copy of a creature token you control.)

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Tap target creature.
Fabled {3}{U} (Then if you cast this for its fabled cost, put it onto the battlefield transformed attached to that creature.)

Reach

Whenever Dryad of Rippling Leaves enters or you draw a card except during your draw step, scry 1. (To scry 1, look at the top card of your library. You may put that card on the bottom of your library.)

{T}: Untap target basic land.

Haste
Ward—Pay 3 life.
{R}, Tap an untapped artifact you control: Drysand Mole gets +1/+0 until end of turn. Up to one target creature can't block it this turn.

Assault {1}{R} (Whenever this attacks, if it has no +1/+1 counters on it, you may pay its assault cost to put a +1/+1 counter on it.)
Whenever a creature you control assaults, creatures you control get +1/+0 until end of turn.

Choose three. You may choose the same mode more than once.
• Target player creates two 1/1 white Soldier creature tokens. They gain haste until end of turn. Exile them at the beginning of the next end step.
• Dthan's Confluence deals 2 damage to target creature or planeswalker.
• Target creature gains double strike until end of turn.

When Dthan's Daggers enters, you may attach it to target creature you control.
Whenever equipped creature attacks, it gets +3/+0 and gains first strike until end of turn.
Equip {3}{R}

Menace, haste
Whenever another creature dies, you get a blood counter.
{B}{R}, Pay two blood counters: Return Dthan, Who Bloodies the Sands from your graveyard to the battlefield.

Enchant creature
Enchanted creature has +2/+0 and has haste.
Quickdraw {R} (When a creature you control blocks or becomes blocked, you may cast this spell for {R}.)

When Dualglaive Acolyte enters, create a green Aura enchantment token named Calamighty attached to target creature. The token has enchant creature and “Enchanted creature gets +1/+1 and can't be blocked by creatures with power 2 or less.”

Equipped creature is a Dragon and has base power and toughness 4/4, flying, and “{2}: This creature gets +1/+0 until end of turn.”
Equip {3}

Double strike
{3}{R}{W}: Create Hao'Tai's Blessing, a legendary red and white Aura enchantment token with enchant creature and “Enchanted creature gets +3/+3 and has flying” and attach it to Duan, the Fabled Rider.

When Duchess Odelia VII enters, search your library for a nonland permanent card with mana value 1 or less, reveal it, put it into your hand, then shuffle.