|First Appearance||Devilman (TV):Ep 6|
Yamaguchi was a Japanese man with neat black hair and large black glasses, he had brown eyes and wore a large white lab coat.
Yamaguchi was working late at night to wax over an ancient skull for his boss. However while his back is turned the demon Rockfel absorbs the skull and pours the boiling wax over Yamaguchi before leaving. Yamaguchi gathers enough strength to warn Dr. Makimura before either passing out or dying.