msem-instigator

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.

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.

Whenever Drownyard Colossus or another creature you control enters, any number of target players each mill cards equal to that creature's toughness.
{2}{U}{B}, {T}: Draw a card, then create a 0/3 blue Crab creature token with “{T}: Target player mills a card.”

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.

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.

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.

If an opponent controls more lands than you, search your library for up to three basic land cards, reveal them, put them into your hand, then shuffle.

Equipped creature gets +1/+0 and has first strike.
As long as another artifact named Dueling Blades is attached to a creature you control, equipped creature has double strike.
Equip {1}

Target creature gets +2/+0 until end of turn and can't be blocked except by three or more creatures this turn.
Flashback {U/R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Untapped creatures you control get +1/+1.
Soldiers you control have vigilance.

As Duke Gerard Hoff enters, an opponent gains control of it.
Duke Gerard Hoff can't attack its owner or planeswalkers that player controls.
Creatures your opponents control get +2/+1.

When Duncaster Nightwatcher enters and whenever you cast a noncreature spell, create a 1/1 colorless Human creature token.
Whenever you attack with three or more creatures, return target noncreature, nonland card with mana value 3 or less from your graveyard to your hand.

At the beginning of your upkeep, choose one —
• Create a colorless artifact token named Etherium Cell with “{T}, Sacrifice this artifact: Add one mana of any color.”
• Put a +1/+1 counter on another target artifact. It becomes a 0/0 Construct artifact creature if it isn't a creature.

Menace
Whenever a creature you control deals combat damage to a player, exile the top card of that player's library. They lose life equal to that card's mana value.

Copy target spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Flash
When Duplicated Dismantler enters, if you cast another spell this turn, return target spell to its owner's hand.

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

When Dusk Lieutenant enters, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)
Once each turn, when you discard a card during your turn, each opponent discards a card.

When Duskling Stalker dies, if it didn't have any counters on it, return it to the battlefield with your choice of a deathtouch, lifelink, or +1/+1 counter on it.

Each other nontoken Elf and/or Warrior you control enters with an additional +1/+1 counter on it.
{G}{G}, {T}, Remove two +1/+1 counters from among creatures you control: Create two 1/1 green Elf Warrior creature tokens.

{T}: Add {C}.
{1}, {T}: Target player exiles a card from their graveyard. If a creature or planeswalker card is exiled this way, create a Vessel token. (It's an enchantment with “{2}, Sacrifice this enchantment: Create a 1/1 white Spirit creature token with flying.”)

Dutiful Chasqui gets +2/+1 as long as you control two or more other creatures that share a name with it.
A deck can have any number of cards named Dutiful Chasqui.

Prowess
Whenever you cast an instant or sorcery spell, if its mana value is less than or equal to Dwarven Twinslinger's power, copy that spell. You may choose new targets for the copy.