After the death of his best friend and mentor Goro Numata by Black Satan's attempt to convert him into a Kikaijin cyborg, Shigeru Jo vowed revenge. Faking ignorance of their part in the murder and portraying himself as a villain, Shigeru tricked Black Satan's scientists into converting him into a cyborg, Electro-Wave Human Stronger. Brought before Black Satan's leader to swear loyalty to him, Shigeru revealed his true colors as he transformed. Saving a fellow incomplete cyborg named Yuriko Misaki, Electro-Wave Human Tackle, as they escaped, Shigeru introduced himself to her as the two of worked together against Black Satan. Shigeru was then known as Kamen Rider Stronger, while whether Tackle is a Kamen Rider or not is a more complicated matter.