Sento Kiryu (桐生 戦兎, Kiryū Sento) is the main protagonist of Kamen Rider Build. He is a physicist who transforms into Kamen Rider Build (仮面ライダービルド, Kamen Raidā Birudo) to uncover the truth behind his mysterious past. Main article: Takumi Katsuragi Takumi Katsuragi was the infamous "Devil's Scientist" researcher at the Touto Institute of Advanced Matter Physics, who alongside his father Shinobu Katsuragi was involved in the creation of Project Build, which was completed after Takumi had joined Fau
