Why Must They Fight?

Why Must They Fight? (彼らはなぜ戦わなければならなかったのか) is the forty-sixth episode of Kamen Rider Drive. This episode features the debut appearance of a fusion form between Kamen Riders Mach and Chaser. This also features the proper debut of the Sigma Circular in mecha form.

Synopsis
Chase protected Go in exchange for his life. Only after seeing him perish does Go realize the impact Chase had on him. Then, Gold Drive, whom Chase supposedly used his final strength to defeat, appears before him. Meanwhile, Shinnosuke heads for the rooftop of the SSDC alongside Heart and Medic. A device that would turn humanity into data, the Sigma Circular, is there. However, right before they could reach the place, the second Global Freeze hits…

Plot
to be added

Cast

 * Shinnosuke Tomari (泊 進ノ介): Ryoma Takeuchi (竹内 涼真)
 * Kiriko Shijima (詩島 霧子): Rio Uchida (内田 理央)
 * Chase (チェイス): Taiko Katono (上遠野 太洸)
 * Go Shijima (詩島 剛): Yuu Inaba (稲葉 友)
 * Jun Honganji (本願寺 純): Tsurutaro Kataoka (片岡 鶴太郎)
 * Rinna Sawagami (沢神 りんな): Rei Yoshii (吉井 怜)
 * Kyu Saijo (西城 究): Kenta Hamano (浜野 謙太)
 * Genpachiro Otta (追田 現八郎): Taira Imata (井俣 太良)
 * Narration (ナレーション), Drive Driver's voice (ドライブドライバーの声): Chris Peppler (クリス・ペプラー)
 * Heart (ハート): Tomoya Warabino (蕨野 友也)
 * Medic (メディック): Fumika Baba (馬場ふみか)
 * Tenjuro Banno (蛮野 天十郎): Masakazu Morita (森田 成一)

Guest cast

 * Sigma Circular (シグマサーキュラー): Ayumi Fujimura (藤村 步)

Shift Cars & Signal Bikes

 * Car Used:
 * Type Change: Shift Tridoron
 * Tire Exchange:
 * Type Used:
 * Type Tridoron
 * Tire Blending used in Type Tridoron:
 * Kouji Genbar
 * Bike Used:
 * Form Change: Signal Mach, Signal Chaser
 * Signal Exchange:
 * Form Used:
 * Mach

Errors

 * to be added