As the theme song denotes, no one knows who Gekko Kamen is. He is a lone figure dressed entirely in white, who mysteriously appears when danger is afoot. While he appears to be a regular human, he is exceptionally gifted in many areas including unarmed combat and gymnastics. He is an expert motorcycle rider and a superb marksman. (Source: AniDB)
Watch Seigi wo Aisuru Mono Gekkou Kamen episode 1 online — subbed and dubbed, with automatic AniList / MyAnimeList progress sync.