Koichi Domoto is a Japanese performer known for his extensive career as a singer and actor, with a more limited but notable history in anime voice acting. He was born on January 1, 1979, in Ashiya, Hyogo, Japan, and has been active in the entertainment industry since 1992. He is widely recognized as a member of the influential J-pop duo KinKi Kids.

Domoto's work as a voice actor in anime is infrequent but has garnered attention due to his high profile in other entertainment fields. His first major anime voice role was in the television series Jyu-Oh-Sei, where he provided the voice for the adult version of the character Thor in 2006. This initial foray into voice acting was followed by a significant gap before his next anime appearance.

After approximately two decades, Domoto returned to voice acting for a role in a major anime film. He was cast as Zodon in the 2026 movie That Time I Got Reincarnated as a Slime: Tears of the Azure Sea, the second feature film in the popular Tensura franchise. This role marked his first time performing as a voice actor in an anime film. Zodon is a minister in the underwater kingdom of Kaien and serves as a pivotal antagonist in the film's story, with Domoto noting that the character was unlike any he had played before. He expressed delight in being given the opportunity to join the well-known series and that he found the recording process to be enjoyable.

Beyond these specific voice roles, Domoto has an extensive career as a live-action actor and stage performer. He has starred in numerous Japanese television dramas, with notable leading roles in series such as Bokura no Yūki Miman City, Sushi Ōji!, and Remote. Domoto is also renowned for his work in theatre, particularly his long-running musical Endless SHOCK, which has been a significant part of his career. While his catalogue of anime voice credits is sparse, his performances in Jyu-Oh-Sei and the Tensura movie stand as his key achievements in this specific field.