“Book Descriptions: Ultra Despair Hagakure (絶対絶望葉隠 Zettai Zetsubō Hagakure) is an in-game novella centered around Yasuhiro Hagakure and Kanon Nakajima that is unlocked after beating Danganronpa Another Episode: Ultra Despair Girls, and is told by the two characters' points of view.
As it is considered a spin-off novel and the events of the story are never mentioned in other content, its canonicity is unclear.” DRIVE