Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~ (仮面ライダービルド ハザードレベルを上げる ～７つのベストマッチ～,Kamen Raidā Birudo Hazādoreberu o Ageru Nanatsu no Besuto Matchi) is a web-exclusive series of Kamen Rider Build, which is released on Toei's official YouTube channel. 
to be added
Continuity and Placement
The first two chapters of the web series takes place between episodes 21 and 22.. The Final Chapter takes place 1 month after the Next Chapter.