Rin Kasahara, also known by the pen name RIN, is a Japanese manga artist and manga original creator born on June 16, 1956, in Kanagawa Prefecture, Japan. Kasahara began his career in the manga industry after working as an assistant to Tatsuo Nitta. He made his professional debut in 1980 with the manga Seishoku Gurentai, which was published in the Weekly Manga Action special edition magazine.

Throughout the 1980s and 1990s, Kasahara consistently created original serialized works. One of his notable original manga from this period is Mellow, a seinen manga that was adapted into a single-episode OVA anime released on July 23, 1993. The story of Mellow revolves around a cross-dressing teacher who is tasked with handling a delinquent class. Kasahara is credited as the original creator for this anime adaptation, with the OVA representing a key example of his work being brought to the screen. Another of his manga from this era, Joro, was also adapted into an OVA.

Despite steady output, Kasahara struggled to achieve major commercial success for many years. By the late 2000s, the difficulty of earning a consistent living from manga led him to consider ending his career. A significant turning point came in 2010 when he adopted the new pen name RIN. In collaboration with his longtime friend, manga artist Keisuke Itagaki, he created the manga Dogenzen. The series, noted for its innovative setting, became a substantial hit, with its collected tankobon volumes selling a cumulative 700,000 copies. This success marked a dramatic comeback for Kasahara, and he has continued to publish works under the RIN name. His body of work includes original manga, nonfiction pieces, and work as an original creator for other artists' projects.