Oni der lautlosen Klinge

Ninjutsu {4}{U}{B} ({4}{U}{B}, bringe einen ungeblockten Angreifer, den du kontrollierst, auf deine Hand zurück: Bringe diese Karte aus deiner Hand getappt und angreifend ins Spiel.)
Immer wenn der Oni der lautlosen Klinge einem Spieler Kampfschaden zufügt, schaue dir die Karten auf der Hand dieses Spielers an. Du kannst eine Karte darunter, die kein Land ist, wirken, ohne ihre Manakosten zu bezahlen.

Oni hoja silenciosa

Ninjutsu {4}{U}{B}. ({4}{U}{B}, regresar un atacante no bloqueado que controles a la mano de su propietario: Pon esta carta en el campo de batalla de tu mano girada y atacando.)
Siempre que el Oni hoja silenciosa haga daño de combate a un jugador, mira la mano de ese jugador. Puedes lanzar una carta que no sea tierra de allí sin pagar el coste de maná de esa carta.

Oni à la lame silencieuse

Ninjutsu {4}{U}{B} ({4}{U}{B}, renvoyez en main un attaquant non-bloqué que vous contrôlez : Mettez sur le champ de bataille cette carte, engagée et attaquante, depuis votre main.)
À chaque fois que l'Oni à la lame silencieuse inflige des blessures de combat à un joueur, regardez la main de ce joueur. Vous pouvez lancer une carte non-terrain qui s'y trouve sans payer son coût de mana.

Oni Lama Silenziosa

Ninjutsu {4}{U}{B} ({4}{U}{B}, Riprendi in mano una creatura attaccante non bloccata che controlli: Metti questa carta sul campo di battaglia dalla tua mano TAPpata e attaccante.)
Ogniqualvolta l'Oni Lama Silenziosa infligge danno da combattimento a un giocatore, guarda la mano di quel giocatore. Puoi lanciare una carta non terra da quella mano senza pagare il suo costo di mana.

静刃の鬼

忍術 {4}{U}{B} （{4}{U}{B}, あなたがコントロールするブロックされていない攻撃クリーチャー１体を手札に戻す：あなたの手札からこのカードをタップ状態の攻撃クリーチャーとして戦場に出す。）
静刃の鬼がいずれかのプレイヤーに戦闘ダメージを与えるたび、あなたはそのプレイヤーの手札を見る。 あなたはその中の土地でないカード１枚をマナ・コストを支払うことなく唱えてもよい。

Silent-Blade Oni

Ninjutsu {4}{U}{B} ({4}{U}{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, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

Outlaws of Thunder Junction Commander

Ninjutsu {4}{U}{B} ({4}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Silent-Blade Oni deals combat damage to a player, look at that player's hand. You may cast a spell from among those cards without paying its mana cost.

New Capenna Commander

Commander 2018

Ninjutsu {4}{U}{B} ({4}{U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever Silent-Blade Oni deals combat damage to a player, look at that player's hand. You may cast a nonland card in it without paying that card's mana cost.

Planechase Anthology

Planechase 2012

If you cast a card without paying its mana cost, you can't choose to cast it for any alternative costs, such as evoke or the alternative cost provided by the morph ability. If it has {X} in its mana cost, X must be 0. However, you can pay optional additional costs, such as kicker, and you must still pay mandatory additional costs, such as the one on Fling.

If you cast a permanent spell this way, it will enter under your control when it resolves. If you cast an instant or sorcery spell this way, that card will be put into its owner's graveyard when it resolves.

The nonland card you cast via the triggered ability is cast as part of the resolution of that ability. Timing restrictions based on the card's type are ignored. Other restrictions, such as "Cast [this card] only during an opponent's turn," are not.