Having finally taken the burden to becoming the true OOO, Eiji fights to prevent Doctor Maki from realizing his "perfect end" while working to reach his ultimate desire of being there for others and having others be there for him.
| Actor | Role |
|---|---|
 Shu WatanabeEiji Hino / Kamen Rider OOO | Eiji Hino / Kamen Rider OOO |
 Ryosuke MiuraAnkh / Shingo Izumi | Ankh / Shingo Izumi |
 Riho TakadaHina Izumi | Hina Izumi |
 Asaya KimijimaShintaro Goto / Kamen Rider Birth | Shintaro Goto / Kamen Rider Birth |
 Takashi UkajiKousei Kougami | Kousei Kougami |
 Hiroaki IwanagaAkira Date / Kamen Rider Birth Prototype | Akira Date / Kamen Rider Birth Prototype |
 Yū KamioKiyoto Maki | Kiyoto Maki |
 Mayuko ArisueErika Satonaka | Erika Satonaka |
| MMarie KaiChiyoko Shiraishi | Chiyoko Shiraishi |
 Ryuki TakahashiKengo Utahoshi | Kengo Utahoshi |
 Yoshiko SengenYuki Jojima | Yuki Jojima |
| YYusuke YamadaUva | Uva |