Genju of the Fens

Enchant Swamp
{2}: Until end of turn, enchanted Swamp becomes a 2/2 black Spirit creature with "{B}: This creature gets +1/+1 until end of turn." It's still a land.
When enchanted Swamp is put into a graveyard, you may return this card from your graveyard to your hand.

Goryo's Vengeance

Return target legendary creature card from your graveyard to the battlefield. That creature gains haste. Exile it at the beginning of the next end step.
Splice onto Arcane {2}{B} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Hero's Demise

Hired Muscle

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on this creature.
At the beginning of the end step, if there are two or more ki counters on this creature, you may flip it.

Scarmaker

Remove a ki counter from Scarmaker: Target creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Hired Muscle // Scarmaker

Hokori, Dust Drinker

Lands don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player untaps a land they control.

Horobi's Whisper

If you control a Swamp, destroy target nonblack creature.
Splice onto Arcane—Exile four cards from your graveyard. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Ink-Eyes, Servant of Oni

Ninjutsu {3}{B}{B} ({3}{B}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Ink-Eyes deals combat damage to a player, you may put target creature card from that player's graveyard onto the battlefield under your control.
{1}{B}: Regenerate Ink-Eyes.

Kyoki, Sanity's Eclipse

Whenever you cast a Spirit or Arcane spell, target opponent exiles a card from their hand.

Mark of the Oni

Enchant creature
You control enchanted creature.
At the beginning of the end step, if you control no Demons, sacrifice this Aura.

Nezumi Shadow-Watcher

Sacrifice this creature: Destroy target Ninja.

Ogre Marauder

Whenever this creature attacks, it gains "this creature can't be blocked" until end of turn unless defending player sacrifices a creature of their choice.

Okiba-Gang Shinobi

Ninjutsu {3}{B} ({3}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, that player discards two cards.

Patron of the Nezumi

Rat offering (You may cast this spell any time you could cast an instant by sacrificing a Rat and paying the difference in mana costs between this and the sacrificed Rat. Mana cost includes color.)
Whenever a permanent is put into an opponent's graveyard, that player loses 1 life.

Psychic Spear

Target player reveals their hand. You choose a Spirit or Arcane card from it. That player discards that card.

Pus Kami

{B}, Sacrifice this creature: Destroy target nonblack creature.
Soulshift 6 (When this creature dies, you may return target Spirit card with mana value 6 or less from your graveyard to your hand.)

Hundred-Talon Strike

Target creature gets +1/+0 and gains first strike until end of turn.
Splice onto Arcane—Tap an untapped white creature you control. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Betrayers of Kamigawa