Kamen Rider Build has chosen to represent Touto in the battle against Hokuto's strongest Rider, Grease. The victor will claim the Pandora Box and the war's victory. Getting prepared for this kind of fight is not easy. Sento has decided to rise up to end the suffering and protect the city of Touto. Sento wants to avoid using the dangerous power of the Hazard Trigger as much as possible, but when Grease proves to be too strong, he reaches for it… (Source: kamenrider.fandom.com)