Ruito Koga is a Japanese voice actor and actor born on July 29, 2004, in Kanagawa Prefecture, Japan. Affiliated with the talent agency At Production, he stands 158cm tall and lists dance and kendama as his hobbies and special skills.

Koga began his career as a child actor, making his stage debut in the 2014 musical The King and I. He subsequently appeared in numerous stage productions, including the 2.5-dimensional stage adaptations of Nintama Rantaro and Brothers Conflict, as well as the musical Billy Elliot the Musical. In 2018, he was selected for lead roles in both Lisa and Gaspard The Musical and The Poupelle of Chimney Town, which drew significant attention to his work as a stage performer.

Koga's voice acting career began in 2014 with his role as Sousuke (credited as Kusuke in some sources) in the television anime series Mushishi: The Next Chapter (also known as Mushishi Zoku Shou). This series, the sequel to the acclaimed Mushishi, featured Koga in a guest role for episode 21. He was also cast in the 2014 anime Future Card Buddyfight.

Other notable voice roles include a younger version of the protagonist Katsuhira Agata in the 2016 series Kiznaiver, a kindergartener in the 2016 anime Sweetness & Lightning, and a child role in the Japanese dub of the Disney Pixar film The Good Dinosaur. In 2024, he took on the role of 4S in the second season of NieR:Automata Ver 1.1a. His work in the 2024 Kamen Rider Gavv franchise, voicing the character Jeeb Stomach in both the television series and the film Kamen Rider Gavv: The Movie - The Invader from the Sweets House, marks a foray into live-action tokusatsu.