msem-instigator

When Kinken, the Dragon's Breath enters the battlefield, draw a card, then choose a creature card name.
Whenever a creature you control with the chosen name attacks, you may pay {1}. If you do, create a token that's a copy of it and that's tapped and attacking, except it isn't legendary. Exile the token at the beginning of the end step.

When Kiri Yoroi enters the battlefield, create a 2/2 colorless Spirit creature token and attach Kiri Yoroi to it.
Equipped creatures you control get +1/+1.
Equip {2}

Spirited (When this creature enters the battlefield, you may activate one of its activated abilities without paying its cost.)
{3}{W}{B}: Create a 0/1 white and black Human Advisor creature token with “When this creature enters the battlefield, target creature can't attack or block until this creature leaves the battlefield.”

Flash
Spirited (When this creature enters the battlefield, you may activate one of its activated abilities without paying its cost.)
{W}{B}: Kirishima's Escort gets +1/+1 and gains first strike until end of turn.

When Kiyomi's Disciple enters the battlefield, put target creature card from a graveyard onto the battlefield under your control. When Kiyomi's Disciple is no longer on the battlefield, that creature's controller sacrifices it.

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, you may return target creature card from your graveyard to your hand.
Equip {2}

When Kizoku Valiant enters the battlefield or dies, you gain 2 life.
Art of war — At the beginning of your end step, if Kizoku Valiant dealt damage to an opponent this turn, put a +1/+1 counter on it.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Whenever Knight of the Cockatrice attacks, you may pay {1}{R}. When you do, target creature can't block this turn.

Prowess
Whenever Knight-Academic attacks, scry 1.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
At the beginning of combat on your turn, Knotwood Lumberer gains your choice of vigilance or trample until end of turn.

Vigilance
Whenever Kodaichi Bladedancer attacks, target creature gets +2/+2 until end of turn.

At the beginning of your end step, if an opponent lost life this turn, Kogane the Crimson Consort deals 2 damage to each opponent and you gain 2 life.

Double strike
Art of war — At the beginning of your end step, if Kogane's Swordmaster dealt damage to an opponent this turn, put a +1/+1 counter on it.

Equipped creature gets +2/+2.
Art of war — At the beginning of your end step, if equipped creature dealt damage to an opponent this turn, create a 1/1 colorless Samurai creature token.
Equip {2}

Creatures you control have protection from legendary. (Those creatures can't be blocked, targeted, dealt damage, or enchanted by anything legendary.)

Konoe's Lieutenant gets +1/+1 as long as an opponent controls a legendary permanent.

Flying
Whenever you cast a spell, exile the top card of your library.
At the beginning of your end step, put a card exiled with Korephyr, Riddle Sage into its owner's hand. Put each other card exiled with Korephyr on the bottom of its owner's library in a random order.
{3}{U/B}: Scry 2.

Art of war — At the beginning of your end step, if Kowareta Informant dealt damage to an opponent this turn, draw a card, then discard a card.

Art of war — At the beginning of your end step, if Kowareta Scrounger dealt damage to an opponent this turn, you may search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Once each turn, when you sacrifice a land, you may add one mana of any color. Until end of turn, you don't lose this mana as steps and phases end.

Krismite Shard enters the battlefield tapped.
{1}, {T}, Sacrifice Krismite Shard: Aetherize target creature you control. (To aetherize, create a token that's a copy of it, then exile that token.)

{T}: Add {C}.
When Krismite Vault is put into a graveyard from the battlefield, create a tapped colorless artifact token named Mox Krismite with “{T}: Add one mana of any color.”

Target creature you control deals damage equal to its power to target player or planeswalker.
Inscribe {4}{R}{G} ({4}{R}{G}: Exile this card from your hand inscribed on a creature you control. Whenever that creature attacks, its controller may cast a copy of the inscribed card without paying its mana cost. Inscribe only as a sorcery.)

Sacrifice Kumo-no-Oni: Prevent all combat damage that would be dealt this turn.

Flash
Spirited (When this creature enters the battlefield, you may activate one of its activated abilities without paying its cost.)
{1}: Remove target attacking creature you control from combat and untap it.