Kenji Ōtsuki, born on February 6, 1966, in Nakano, Tokyo, is a Japanese rock musician, singer-songwriter, and author who has created several notable original works that have been adapted into other media. While his primary fame comes from his lengthy career as the vocalist for bands such as Kinniku Shōjo Tai (also known as Kinniku Shōnen Shōjo Tai) and Tokusatsu, he is also a recognized writer of novels, essays, and manga source material. In his youth, Ōtsuki aspired to become a manga artist alongside a classmate, an early ambition that foreshadowed his eventual foray into literature and adaptation-based projects.

Ōtsuki began his literary career in the early 1990s while still active with his bands. He is best known for the coming-of-age novel series Gummi Chocolate Pine (titled Gumi Chokoreeto Pain in Japanese), which was published in three parts, Gumi, Chokoreeto, and Pain, between 1993 and 2003. The story, a semi-autobiographical account of a socially awkward and angsty high school student in the 1980s who immerses himself in underground rock music, film, and literature, has become a touchstone for fans of Japanese youth culture and music. The novel was adapted into a live-action film in 2007, directed by Keralino Sandorovich (also known as Kera), a long-time collaborator of Ōtsuki's from the music scene. The film had its international premiere in 2008. Additionally, the novel was adapted into a manga series, which was published by Kodansha beginning in 2001, with art by Sasaki and Shimizu.

Beyond Gummi Chocolate Pine, Ōtsuki has written other novels, including Stacy, which was later adapted into a film and a manga. He has also published numerous essays, such as Ooken no nohohon nikki, and has won the prestigious Seiun Award for Best Short Story for two consecutive years, 1994 and 1995, for his science fiction writing. His literary style is notably influenced by the Showa Keihaku Tai, or Frivolous Shōwa Style, a genre known for its light, ironic, and often self-referential tone.

As an original creator, Ōtsuki's works are characterized by a raw, humorous, and often painfully honest portrayal of adolescent disillusionment, obsession with subculture, and the gap between aspiration and reality. His identity as a musician deeply informs his writing, with themes of rock music, band dynamics, and the creative drive serving as central pillars of his most famous work. While he is not primarily a manga artist himself, his original stories have proven fertile ground for adaptation into visual media, making him a significant figure who bridges the Japanese rock music and literary subcultures. His influence is noted for capturing the spirit of a particular generation of Japanese youth who found identity and community in underground and alternative culture during the 1980s and 1990s.