After the civil war that tore apart Japan, the new governors of Touto, Hokuto and Seito work together to reunify the country. But they are actually members of an extraterrestrial race called "Blood Tribe", the same species as Evolto who arranged their government positions to commence their plan to destroy Earth as they have done to Mars and previous planets before.
Kamen Rider Build: Be the One
After Japanese Civil War, the newly appointed governors of each region: Seito, Hokuto, and Touto now support each other in their mission to reunify Japan, however they are secretly members of Evolto's home clan known as the Blood Tribe.
