In 2015, Denkou Choujin Gridman inspired an animated short directed by Akira Amemiya and produced by Studio Trigger for the Japan Animator Expo. Entitled, Denkou Choujin Gridman: boys invent great hero (電光超人グリッドマン boys invent great hero Denkō Chōjin Guriddoman Boizu Inbento Gurēto Hīrō), it debuted on January 16, 2015. It features the return of Takeshi Todo and the brief appearance of Gridman Sigma (グリッドマンシグマ Guriddoman Shiguma), another Hyper Agent like Gridman who never made it to the show's final cut. The entire short took place in 22 years after Gridman's final battle with Khan Digifer. Takeshi Todo, a former brainwashed servant of Khan, reflects on the past incidents as monster attacks take place in real life. Using the Acceptor, he transforms into Gridman Sigma before facing the monsters.
22 years ago... A boy, Takeshi Todo, attempted to take over the world together with the devil of the Computer World. He reformed himself after the battle and now needs the power of the Hyper Agent. Again, the evil is going to appear in the real world. A materialized monster is now approaching! Enter the battle code! The Access Code is..."GRIDMAN".
- Character design: Yusuke Yoshigaki
- Key Animator: Akira Amemiya, Yusuke Yoshigaki
- In-between Animation checker: Nahoko Kosugi, Yoshie Endo
- In-between Animator: Kana Yamaguchi, Yukina Kai, Mayumi Nakamura, Takeshi Ikezawa
- Color Design/Color Coordination Inspection: Akemi Nagao
- Coloring Cooperator: Studio GIMLET, T2 studio, Studio OZ, Taikan
- Animation Studio Coloring Manager: Kosuke Kobashi
- Texture Painter: Yukiko Kakita(T2 Studio), Emi Nonaka
- Digital Animator: Masato Takeuchi
- Administer of Backgroud: Yukihiro Watanabe
- Computer graphics: Shogo Tsurii, Kayoko Zama, Hiroyasu Kobayashi
- CGI Manager: Yuki Hanzawa
- Cinematographer: Eiji Tsuchida
- Filming: Tomoyuki Sakurada, Emi Nonaka, Sou Shi Ken
- Editor: Hidemi Li
- Music: "Yume no HERO"
- Composer: Kisaburo Suzuki, "Motto kimi wo shireba"
- Composer: Kisaburo Suzuki
- Music Cooperation: FlyingDog, Inc.
- Cast: Koichi Yamadera
- Sound Effect Director: Haru Yamada（sound team - donjuan）
- Line Manager: Shoichiro Taguchi
- Line Assistant: Kazuya Masumoto
- Animation Production: TRIGGER
- Director: Akira Amemiya
- "Yume no HERO"
- "Motto kimi wo shireba"