كتاب رواية فن النينجيتسو

If your opponent controls a card: Set 1 "Ninjitsu Art" Spell/Trap and/or 1 "Ninja" monster (1 from your Deck and 1 from your GY), except "Novel Ninjitsu Art Book". If this Set card is sent to the GY: You can target 1 face-up monster on the field; change it to face-down Defense Position. You can only use each effect of "Novel Ninjitsu Art Book" once per turn.