Mizushima Hiro, born Saito Tomohiro, is a Japanese actor, businessman, YouTuber, and novelist. From childhood until his graduation from elementary school, he studied in Zurich, Switzerland. He is fluent in English. He returned to Japan when he entered junior high. He took the entrance exams and was accepted into Toin Gakuen, an international school located in Yokohama, for junior high and high school. He belonged to the soccer club in middle and high school. He suffered an injury in high school and stopped playing soccer. He was admitted to Keio University and graduated from there in March 2008. In 2004, during his time in college, he decided to study abroad. Seeking to gather funds in order to do so, a school senior introduced him to a modeling job. After some time working as a fashion model under Gig Management, he was approached by a talent agency and transferred to Ken-on. He would go on appearing alongside Hayami Mokomichi in 2005's "Gokusen". Following that, he mostly appeared in numerous dramas in small and supporting roles before landing the lead role in 2006's "Kamen Rider Kabuto". He would also appear in the following year's "Hanazakari no Kimitachi e". Since then, he appeared in the lead role in numerous works. He would also go on to co-produce the 2014 movie "Kuroshitsuji" where he also starred as Sebastian Michaelis. In addition to his acting activities, he's been a published author since the 2010 release of his book "KAGEROU" which also won the 5th Poplar Publishing Novel Award. Reportedly, he submitted the book under the name Saito Satoshi so the editor wasn't aware who the winner was until she went to meet him. Despite claims that he was retiring to focus on writing in 2010, his wife Ayaka helped to confirm that he was not retiring from the entertainment industry. He also appeared in HBO's "Girls" in 2015. From 2016, he established 3rd i connections. He was also appointe Watch drama online for free.