|This article is about a/an actor in Kamen Rider Kabuto.|
Tomohiro Saitō (齋藤 智裕 Saitō Tomohiro), better known under his stage name Hiro Mizushima (水嶋 ヒロ Mizushima Hiro) is a Japanese actor model who portrayed Soji Tendo/Kamen Rider Kabuto and Soji Kusakabe/Dark Kabuto in 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.
Mizushima has also ventured into writing, where he took on the pen name Satoshi Saitō (齋藤 智 Saitō Satoshi). In 2010, he wrote and published his first novelKagerou, was the winner of 5th Popular Publishing Grand Prize for Fiction.
- As Mizushima was raised in Switzerland, he is fluent in both Japanese and English.
- Mizushima was not contacted to reprise his role in Kamen Rider Heisei Generations FOREVER, but wished the film great success.
- Since 2009, Mizushima has been married to singer Ayaka Iida. They have two daughters, born in 2015 and 2019.
Hiro's Youtube Channel
Hiro Mizushima, is Hiro's personal Youtube Channel where he often makes cooking videos and vlogs.
Mizushima does a series about Japanese cooking called Hiro-Meshi. One episode featured his co-star Yuki Sato, where Misuzhima served "saba-miso", a staple of Soji Tendo's cooking.  In the interview, Mizushima reveals he had watched Sato's reprisal in Kamen Rider Zi-O. 
Mizushima revealed that unlike his character, he hated eating fish due to its "aquarium"-like taste and bad smell. However, he 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.