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Ikazuchi, originally designated Spaceman Raiden, and also known as Kamen Rider Ikazuchi in his Kamen Rider form, is an Astronaut-Type HumaGear tasked with maintaining Satellite Zea for Hiden who is secretly a sleeper agent for MetsubouJinrai.NET and a minor, but important antagonist in the first entry of the Reiwa era of the Kamen Rider franchise, Kamen Rider Zero-One. He is the one responsible for awakening the Ark for MetsubouJinrai.NET.
Spaceman Raiden was originally manufactured sometime before the Daybreak Incident to serve as the maintainer of Hiden Intelligence's Satellite Ark when it was launched into space. However, on the day that the Ark was supposed to be launched into space, the Daybreak Incident occurred where thousands of HumaGears were hacked by MetsubouJinrai.NET to revolt against humanity. At some point during the catastrophe, Ikazuchi was hacked by MetsubouJinrai.NET and turned into a sleeper agent for them to serve as their spy within Hiden Intelligence.
Spaceman Raiden was later commissioned to serve aboard Satellite Zea alongside his "younger brother" Astronaut-Type HumaGear, Spaceman Subaru, and to "train" him to succeed him as sole maintainer of the satellite. However, the malicious programming he had received from MetsubouJinrai.NET 12 years prior caused him to unknowingly transmit data to them from the Zea Satellite to MetsubouJinrai.NET on which HumaGears were close to reaching Singularity so they could be hacked and turned into Magia for their plans.
Eventually, A.I.M.S. caught on to the possibility that a spy was within Hiden Intelligence due to MetsubouJinrai.NET's repeated attacks against HumaGears close to achieving sentience and investigated the Spaceman Brothers to see if either of them was secretly a spy for the terrorist group. During the investigation though, A.I.M.S. and the HumaGears were attacked by Jin of MetsubouJinrai.NET, who attempted to hack Raiden supposedly to turn him into a Trilobite Magia. Raiden however was seemingly able to resist the hacks and Jin was forced to retreat.
Raiden later went with Aruto Hiden of Hiden Intelligence and Isamu Fuwa of A.I.M.S. to investigate the ground of Daybreak Town to see if they could find MetsubouJinrai.NET's location. Raiden was able to lead the two Riders straight to MetsubouJinrai.NET's base but as they went inside, they were confronted by Jin. Jin then revealed that when he had hacked Raiden, it was not to turn him into a Trilobite Magia but to implant new programming to lead the two Riders there so he could take their keys. Addressing Raiden as "Ikazuchi", Jin awakened the malicious MetsubouJinrai.NET programming inside of him by saying that code word before handing him a ForceRiser and the Dodo Zetsumerise Key, which Ikazuchi used to transform into Kamen Rider Ikazuchi. Aruto and Fuwa then transformed into their Rider forms to combat the hacked HumaGear, but Ikazuchi was able to overpower both of them with the tremendous power of the Dodo key and knock them out of their transformations, allowing him to steal their keys.
After Ikazuchi placed the Hopper and Wolf keys in his belt, Jin tossed him his and Horobi's keys to place in the belt as well. With the necessary keys all brought together, Ikazuchi was able to hack Satellite Zea and use it to reactivate the Ark, allowing MetsubouJinrai.NET to begin their full crusade to rid the world of humanity as per the will of the Ark. However, Aruto as Shining Hopper was able to knock the Progrise Keys out of Ikazuchi, allowing him and Fuwa to retrieve their keys back. After Fuwa stole the newly created Assault Wolf key from Jin, he forcefully activated it and used it to transform into Kamen Rider Vulcan Assault Wolf before using the power of the key to destroy Ikazuchi, leaving behind the Dodo Key for Jin to collect.