Ken Yamaguchi was a Japanese voice actor. He was represented by OYS Produce. His son is a fellow voice actor Kiyohiro Yamaguchi. He was most known for the roles of Ashuraman, The Omegaman, Prisman, Genji Togashi, Flazzard, Black Dragon, and Ein. Yamaguchi died on October 24, 2011, due to acute heart failure.