msem-instigator

As an additional cost to cast this spell, discard a nonland card.
All creatures get -X/-X until end of turn, where X is the discarded card's mana value.

Enchant creature
When Imperative Blessing enters, draw a card.
Enchanted creature gets +2/+2.

Flying
When Imperator Namuzzar enters, search your library for an artifact or enchantment card, reveal it, put it into your hand, then shuffle.
Civilized — Lammasu you control get +2/+2 and have hexproof as long as you control an artifact, a creature, and an enchantment.

First strike, vigilance
Partner with Commander Hyctaleon (When this creature enters, target player may put Commander Hyctaleon into their hand from their library, then shuffle.)
At the beginning of your upkeep, you may search your library for a Soldier card, reveal it, put it into your hand, then shuffle.

Draw three cards.
Lifecycle {3} ({3}, Discard this card: Create two tapped 1/1 colorless Elemental creature tokens.)

When Imperfect Stone enters, mill three cards.
{T}: Add one mana of any color.

Draw a card.
Civilized — Instead draw two cards if you control an artifact, a creature, and an enchantment.

When Imperial Artisan enters, draw three cards, then put two cards from your hand on top of your library in any order.

As Imperial Barracks enters, you may reveal a Mountain or Plains card from your hand. If you don't, Imperial Barracks enters tapped.
{T}: Add {R} or {W}.

All creatures get -2/-2 until end of turn.
Civilized — Instead only creatures your opponents control get -2/-2 until end of turn if you control an artifact, a creature, and an enchantment.

{T}: Add {C}.
{4}, {T}, Put a -1/-1 counter on a creature you control: Draw a card.

At the beginning of your upkeep, scry 2.
Reveal the top card of your library: If a creature card with flying was revealed this way, Imperial Chimera gains flying until end of turn. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

Exile target artifact or enchantment. Its controller creates a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Spirited (When this enters, you may activate one of its activated abilities without paying its cost.)
{1}, {T}: Add one mana of any color. When you do, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Civilized — At the beginning of your upkeep, if you control an artifact, a creature, and an enchantment, you draw a card and you lose 1 life.

Wu Xing (Add effects based on the number of colors of mana spent to cast this spell.)
1 | Create X 1/1 colorless Spirit creature tokens.
5 | Put a +1/+1 counter on each creature you control.

Haste
Whenever a nonbasic land becomes untapped, its controller loses 1 life.

If a source an opponent controls would deal 2 or more damage to you, prevent 1 of that damage.
Civilized — Instead prevent all but 1 of that damage if you control an artifact, a creature, and an enchantment.

When Imperial Diplomats enters, if it's not a token, create a token that's a copy of it, except it has no mana cost.
{T}, Tap an untapped creature you control: Draw a card, then discard a card.

First strike
When Imperial Dragoon enters, target creature gets +2/+0 until end of turn.

Trample
If a creature in Imperial Guardian's pack would deal damage to a permanent or player, it deals twice that much damage instead. (Two or more creatures you control with equal power are in a pack.)

Equipped creature gets +3/+2.
Equip {3}

First strike
Art of war — At the beginning of your end step, if Imperial Kensai dealt damage to an opponent this turn, you may pay 1 life. If you do, put a +1/+1 counter on Imperial Kensai.

Mill four cards, then return a noncreature card from your graveyard to your hand.

Trample
Art of war — At the beginning of your end step, if Imperial Legion dealt damage to an opponent this turn, put two +1/+1 counters on it.