Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~: 1x1

First Chapter

Nariaki Utsumi appears to help Build prepare for the proxy battle with Grease. This chapter takes place immediately after Sento obtains the Fullbottles from Hokuto and Seito in Episode 21, but one week prior to the scene where Build charges at Grease at the proxy duel.