Rarecho is a Japanese creator best known as the director, writer, and voice actor for the death metal singing of the main character in the anime series Aggretsuko. Born on December 10, 1971, in Ibaraki Prefecture, he first gained recognition in the early 2000s as a pioneering web animator, creating popular Flash animations such as Yawaraka Sensha and Kuwagata Tsumami. His early work was notable for being largely self-produced, with Rarecho often handling multiple roles including direction, writing, music composition, and voice acting.

His most prominent voice acting role is the death metal vocals for Retsuko, the protagonist of Aggretsuko. In the Japanese version of the series, Rarecho provides the character's powerful and cathartic singing voice, which serves as her release from daily frustrations. This role extends to related productions, including the holiday special Aggretsuko: We Wish You a Metal Christmas. This voice work is directly tied to his overall creative involvement with the series, as he serves as its director and scriptwriter. His multifaceted contribution to the show is a recurring theme in his career, mirroring his earlier work as an independent online animator.