Shinobumonogatari (忍物語) is the eighteenth part of the Monogatari series. It is the twenty-third book in the series overall and contains the story Shinobu Mustard (しのぶマスタード). It is the first book of the Monster Season.
It was included in the animated Off-Season & Monster Season in 2024.
This tag implicates monogatari_(series) (learn more).