Ryukishi07, born November 19, 1973 in Chiba Prefecture, Japan, is the pen name of a writer, artist, and the founding member of the doujin circle 07th Expansion. His real name has not been publicly disclosed. The pen name is derived from the Final Fantasy term for Dragoon, Ryūkishi, combined with a numeric play on the character name Lenna.

Before his career in fiction, Ryukishi07 studied at a vocational art school and held a position as a civil servant, a background that has informed the recurring themes of social services and family dynamics in his narratives. His younger brother, Yatazakura, inspired by the success of the visual novel Tsukihime, encouraged him to adapt an unproduced stage play script titled Hinamizawa Bus Stop into a digital format. This restructuring became the foundation of his first major work, Higurashi When They Cry, the first chapter of which was released at Comiket in 2002.

Ryukishi07 is the primary creative force behind the When They Cry franchise. This series includes Higurashi When They Cry, the metafictional murder mystery Umineko When They Cry, and the futuristic Ciconia When They Cry. As a writer, he is known for a distinct narrative structure that alternates between lighthearted character interactions and brutal psychological horror. He has described this approach by stating that a story should function like a roller coaster, requiring uplifting moments before delivering scenes of despair. He is a proponent of the fair-play whodunnit, believing that the reader should be provided with enough clues to solve the mystery before the conclusion.

The success of the original sound novels led to numerous media adaptations. The Higurashi franchise alone has seen multiple anime series, including the 2006 adaptation by Studio Deen, Higurashi When They Cry: Kai, Higurashi When They Cry: Rei, Higurashi When They Cry: Kira, and the later sequel series Higurashi: When They Cry – GOU and Higurashi: When They Cry – SOTSU. These works have been credited to him as the original creator. The franchise also includes original video animations such as Higurashi no Naku Koro ni Kaku ~Outbreak~.

Beyond the When They Cry series, Ryukishi07 has collaborated on various high-profile projects. He contributed a partial scenario to Key's visual novel Rewrite and served as the original planner for Konami's Ōkami Kakushi. He wrote the scenarios for Rose Guns Days and Iwaihime. In 2025, Konami enlisted him as the scenario writer for Silent Hill f, specifically seeking a writer who could capture the essence of Japanese horror. His influence extends to the mystery genre, where he has cited Agatha Christie's And Then There Were None as a major influence on his work.