Eken Mine (峰 恵研, Mine Eken; February 15, 1935 – February 6, 2002) was a Japanese actor and voice actor from Nagasaki. He was lifelong friends with Ritsuo Sawa, performing various Kamen Rider characters together; they became convinced of their impact on children after watching them imitate their roles.
Source: “Eken Mine”, English Wikipedia (CC BY-SA 4.0), excerpt