Ryoku Shinsen is a Japanese male voice actor primarily known for his work in adult computer games and doujin audio works, often using a stage name to separate this facet of his career from mainstream roles. He is also credited under his legal name, Kyosuke Kitayama, for other projects. Information about his personal life, such as his exact birth date, is not publicly documented, though he is reported to have blood type B and possesses skill in the Kansai dialect.

Shinsen's career in the voice acting industry has been extensive and highly productive, particularly from the late 2000s onward. He has provided voices for a vast number of characters in visual novels and PC games, building a substantial body of work. His filmography demonstrates a consistent and high-volume output across nearly two decades. For many of his roles, he uses the name Ryoku Shinsen, which serves as his primary alias in the adult gaming industry.

His major voice roles are predominantly in the realm of video games. Some of his earliest credited roles include parts in 2009 titles such as Baldr Sky Dive1 LostMemory and Armored Trooper Votoms. He has been a recurring presence in long-running game series, voicing characters like Karakal Gates in multiple installments of the Maji de Watashi ni Koi Shinasai! franchise and Ryuho Mikuni in the D.C. III ~Da Capo III~ series. His work spans a wide variety of game genres, from fantasy epics like Soukoku no Arterial to school-life stories such as Clover Day's and PRIMAL×HEARTS. In the 2020s, he has continued to take on roles in high-profile titles, including the critically acclaimed Slow Damage and the long-awaited entry in the popular series, the Bishoujo Mangekyou -The Masked Girl-. His role as Spica Diafell in the 2022 web anime Game World Reincarnation (credited for the premium version) represents a crossover into animated series work, based on the game world.

Beyond video games, Shinsen has also been active in the market for drama CDs and audio works, often utilizing binaural recording techniques to create an immersive experience for the listener. Examples of this include his roles as Osamu Fukui in the drama CD Taiikukaikei Danshi no Dousei and as Shitomiya Sono in the doujin CD series Apex predator: Dependence.

While specific information on recurring collaborations with particular directors or studios is not readily detailed, the sheer volume and consistency of his work with various game developers and publishers in the visual novel industry highlight his status as a reliable and in-demand voice actor. His notable achievements lie in his prolific career, having voiced characters in hundreds of games over more than fifteen years, establishing a strong presence within the niche markets he works in.