|Human Host/Form:||Takeshi Todo|
|Height:||Micro ~ 70 m|
|Weight:||0 ~ 56,000 t|
|Place of Origin:||Hyper World|
|Transformation Item:||Grand Acceptor|
|First Appearance:||Denkou Choujin Gridman: boys invent great hero|
Gridman Sigma (グリッドマンシグマ Guriddoman Shiguma) was the proposed ally of Gridman in a sequel series that was never completed or even aired. Sigma would have become the alter ego of Takeshi Todo, a reformed antagonist of the original series. Sigma would have fought a relative of Khan Digifier.
In 2015, Gridman Sigma made his first public appearance in the anime short, Denkou Choujin Gridman: boys invent great hero where he is finally partnered with Takeshi Todo.
Denkou Choujin Gridman: boys invent great hero
Takeshi appeared as an adult in the anime Gridman short. After watching the battles of the previous Gridman, Takeshi is granted a transformation device by the light of several monitors and transforms by shouting 'ACCESS FLASH'. Transforming into Gridman Sigma to face two monsters in the real world.
- Height: Micro ~ 70 m
- Weight: 0 ~ 56,000 t
- Flight Speed: Mach 30
- Origin: Hyper World
- Sigma's blue design would be later used in many other Ultras.
- His face resembles the faces of Jean-Bot and Jean-Nine .
- The reason he has no history or stats is because he never made it on screen since his series was cancelled before development could be made on the character.
||Mirrorman | Falcon | Redman | Red Fighter | Green Fighter | Orange Fighter | Triple Fighter | Jumborg Ace | Jumborg 9 | Fireman | Izenbo | Koseidon|
||Gridman | Servo | WoO | Mirrorman Reflex | Gridman Sigma | Don Shine|
||God Zenon | Dyna Dragon | Mountain Gulliver No. 5 | Reimon | Mirror Knight | Glen Fire | Jean-Bot | Jean-Nine | War God|