Isutoshi (いすとし Isutoshi?) is a Japanese manga artist and the author of Aiki and Aiki-S. His career started in 1994 when he produced work that would later be published in dōjinshi by the Gerumaru (ゲルマル Gerumaru?) circle. His stories usually involve both kinky and funny situations, focusing on the characters' personality and traits, all the while keeping the tone lighthearted and humorous.