Manga
Many manga based on the original Kamen Rider series have been published, but only one was penned and drawn by Ishinomori himself. Ishinomori also was the author of one chapter for Kamen Rider Amazon and the entire Kamen Rider Black manga, but those manga weren't based on the original Kamen Rider series, but its follow ups.
The original manga published in 1971 initially follows a path resembling the first few episodes of the TV series, from basic plot to creature designs. However, when Hongo leaves the TV show and manga's story, each series diverges greatly. In the TV show, Hongo travels abroad to fight Shocker in other countries, but leaves Japan's protection in the hands of another man, Hayato Ichimonji. He was a freelance cameraman who was experimented on by Shocker, but was saved by Hongo, becoming the second Kamen Rider. In the manga, Hongo never left Japan. He was confronted with twelve Shocker Riders and was subsequently mortally wounded during his battle against them. Hayato Ichimonji, one of the twelve Shocker Riders, receives a head injury during the fight and regains his conscience as a result. He then turns against Shocker and succeeds Hongo's role as Kamen Rider. In spite of the damage to his body, Hongo's brain survives and guides Hayato, with both fighting as one.
Hongo eventually returns as a Rider in both stories, but, starting with Hayato's debut, villains and even basic story development greatly diverge between the two versions. The manga portrays a seemingly hopeless battle against Shocker, an organization much bigger than either of the two Riders with ties to governmental conspiracies. The live action TV shows portray the Riders as heroes strong enough to bring down Shocker... only to see it replaced by similar organizations led by Shocker's mysterious leader. The Shocker Riders eventually appear in the TV series too, but in a story unrelated to the manga one, aside from a couple of homages, like Hayato's attire during the story, their appearance and abilities also were different from the manga version. There were also only 6 Shocker Riders, rather than 12 like in the manga.
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