Nu embodies the Japanese hiragana character "ぬ" within the Hiragana Danshi multimedia project. He inhabits a fictional world where humanity lost the ability to read and write alphabets after an unspecified incident. In this setting, Nu is one of the personified syllabaries sought by a calligrapher protagonist striving to restore written language. His design reflects a spunky aesthetic, aligning with the project's theme of giving individual hiragana characters distinct personalities.

Nu joins the collective mission to locate fellow Hiragana Danshi scattered across the world, a journey forming the narrative core across official media, including the theatrical adaptation *Gekijōban Hiragana Danshi ~Jo~*. He contributes vocally to this effort, performing the song "Nununu" on the project's character song album *Itsura no Utakoe*. Nu also provides narrative exposition, delivering the prologue track "Hitobito wa Moji wo Ushinatta" (People Lost the Letters), which establishes the central conflict of a world without written language.