The country of Seito begins their invasion of the country of Hokuto in the next episode of Kamen Rider Build, The Western Phantom.
Written by Shogo Muto
Directed by Kyouhei Yamaguchi
Action Directed by Takeshi Miyazaki (Japan Action Enterprise)
Special Effects directed by Hiroshi Butsuda (Tokusatsu Kenkyuujo)
Build triumphs over Grease. Sento (Atsuhiro Inukai) has ended the war between Touto and Hokuto, but now Seito is gaining control over Hokuto. Friends and family alike are placed under Seito’s control, Kazumi (Kouhei Takeda) and his friends tremble with fury. Sento and Ryuga (Eiji Akaso) go together directly to the Touto Government.
Seito’s Prime Minister Mido (Norimasa Fuke) has declared war on Touto. Mido broadcasts a video showing Kazumi’s friends in restraints. Before anyone realizes it, Kiba (Takuya Yoshimura) turns back to return to Hokuto after transforming into Owl Hazard Smash. He’ll fight to rescue his friends.
But Mido uses a hostage to demand that Kazumi become a weapon for Seito. However, despite being hurt by his friends, Kazumi refuses and decides instead to fight. Sento and Ryuga promise to support Kazumi and his group and return with them to Hokuto, but then the figure of “Seito’s Rider” begins to approach Sento and his party.