is a Japanese manga storywriter, novelist and screenwriter. His original name is Shin Kibayashi (樹林 伸 Kibayashi Shin). He graduated from Tokyo Metropolitan Musashi Senior High School and Waseda University School of Economics & Political Science. The penname "Tadashi Agi" is shared with his sister. Under the name Yuma Ando, he received the 2003 Kodansha Manga Award for shōnen for writing Kunimitsu no Matsuri.
Besides the main pen-name of "Tadashi Agi", Shin Kibayashi also goes by other pennames: