Deathmask Nezumi

As long as you have seven or more cards in hand, this creature gets +2/+1 and has fear. (It can't be blocked except by artifact creatures and/or black creatures.)

Exile into Darkness

Target player sacrifices a creature of their choice with mana value 3 or less.
At the beginning of your upkeep, if you have more cards in hand than each opponent, you may return this card from your graveyard to your hand.

Footsteps of the Goryo

Return target creature card from your graveyard to the battlefield. Sacrifice that creature at the beginning of the next end step.

Ghost-Lit Stalker

{4}{B}, {T}: Target player discards two cards. Activate only as a sorcery.
Channel — {5}{B}{B}, Discard this card: Target player discards four cards. Activate only as a sorcery.

Descendant of Kiyomaro

As long as you have more cards in hand than each opponent, this creature gets +1/+2 and has "Whenever this creature deals combat damage, you gain 3 life."

Gnat Miser

Each opponent's maximum hand size is reduced by one.

Hand of Cruelty

Protection from white
Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)

Infernal Kirin

Flying
Whenever you cast a Spirit or Arcane spell, target player reveals their hand and discards all cards with that spell's mana value.

Kagemaro, First to Suffer

Kagemaro's power and toughness are each equal to the number of cards in your hand.
{B}, Sacrifice Kagemaro: All creatures get -X/-X until end of turn, where X is the number of cards in your hand.

Kagemaro's Clutch

Enchant creature
Enchanted creature gets -X/-X, where X is the number of cards in your hand.

Kami of Empty Graves

Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Kemuri-Onna

When this creature enters, target player discards a card.
Whenever you cast a Spirit or Arcane spell, you may return this creature to its owner's hand.

Kiku's Shadow

Target creature deals damage to itself equal to its power.

Kuon, Ogre Ascendant

At the beginning of the end step, if three or more creatures died this turn, flip Kuon.

Kuon's Essence

At the beginning of each player's upkeep, that player sacrifices a creature of their choice.

Kuon, Ogre Ascendant // Kuon's Essence

Kuro's Taken

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
{1}{B}: Regenerate this creature.

Eiganjo Free-Riders

Flying
At the beginning of your upkeep, return a white creature you control to its owner's hand.

Saviors of Kamigawa