|This article is about a/an actor in Kamen Rider Kabuto.|
Hiro Mizushima (水嶋 ヒロ Mizushima Hiro, born Tomohiro Saitō (齋藤 智裕 Saitō Tomohiro)) is a Japanese actor, writer and model. He was well known as the main protagonist, Souji Tendou and the antagonist, Souji Kusakabe in the tokusatsu series Kamen Rider Kabuto.
Despite Kabuto going on to make later minor appearances, including in recent crossover movies, Hiro Mizushima has yet to reprise either of his roles.
Currently, Hiro is making web videos on his Youtube channel about learning to cook Japanese dishes in a series called Hiro-Meshi.
- Due to being raised in Switzerland, Mizushima is bilingual - being fluent in both Japanese and English, as first exhibited in the 35th Masked Rider Anniversary File segment of Kabuto's 25th episode, where his character pronounces "stronger" and "strongest" in perfect English.
- When replying to an Instagram comment, Mizushima revealed that he was not contacted to reprise his role for Heisei Generations Forever.
- He and Yuki Sato reunited on one of the episodes of his Youtube cooking show "Hiro-Meshi" as Hiro served saba-miso, a staple of his character Souji Tendou's cooking, to Yuki at the end of the episode. 
- During a special 3-part interview, Hiro tells Yuki he watched his scene from Zi-O of Arata Kagami transforming into Kamen Rider Kabuto.
- Surprisingly, Hiro revealed that unlike his character, he hated eating fish due to its "aquarium"-like taste and bad smell. However, Hiro wants to try to eat healthier and thus was willing to try cooking seafood dishes once he learned that certain cooking methods can remove the "fishy" smell and taste and enhance the flavor of fish.