Shiro Kazami was studying biochemistry in college when he stumbled onto a Destron agent committing murder. After saving a woman from the organization and bringing her home, Destron retaliated by killing his entire family—apparently to tie up loose ends. Kamen Rider 1 and 2 showed up just in time to pull Kazami out of the wreckage.
Devastated and alone, Kazami begged the Riders to turn him into a cyborg so he could fight back. They refused at first, but when they got captured raiding Destron headquarters, Kazami charged in after them anyway. He took a fatal wound in the attempt, leaving the Riders with only one option: they converted him into a cyborg and gave him the name Kamen Rider V3.
Content compiled by AnimeList.moe from publicly available sources.
