I remember this series from the 60's when I was a little boy. VHS version of this anime series was available in the late 70's and early 80's and I watched it again back then. The drawings are effective but rather basic, with lots of blank spaces. By the standard of later Japanese animations like "Akira," "Ghost in the Shell," and "Cowboy Bebop," it is rather sparse and basic to say the least.
I compared this animation with cartoonist Jiro Kuwata's original manga graphic novel "Eito-Man," on which the TV series was based. The graphic novel is much better drawn than the TV animation. The drawings in the graphic novel are much more sensual--like many of Kuwata's drawings. It is not very clear from the TV series, but Kuwata's graphic novel shows obvious influences from American comics like "Superman" and "Batman." Some anime connoisseurs say that "Eito-man" is Japan's answer to Superman and Batman.
Kuwata and late story writer Kazumasa Hirai added a touch of Buddhist philosophy to "Eito-Man." The word "Eighth Man" is really referring to Buddhist god Hachi-man. ("Hachi" in Japanese means "eight.") In Buddhism, Buddha reincarnates in the form of different gods to save humans. Hachi-man is one of those gods. Kuwata, who later became a born-again Buddhist, wanted his robot Eighth Man to be a manifestation of the Buddhist god Hachi-man so Buddha can save the innocent people from evil men and women. What is unique about Eighth Man's Buddhist influenced theme is that Eighth Man showed mercy to everyone--even to some villains. In one episode, Eighth Man, with a great risk to his own safety, saved the life of a gangster, who earlier tried to destroy him. The gangster greatly appreciated Eighth Man's deed and promised to reform his ways and be a good person. Story writer Hirai, with his Buddhist philosophy, must have believed that most humans--even some gangsters--can be salvaged. This is greatly different from other superheroes who just kill and destroy villains without showing any mercy to them. Even as a child in the 60's, I was greatly impressed with Eighth Man's sense of mercy and forgiveness.
Unfortunately, Jiro Kuwata could not complete his graphic novel series "Eito-man." In the mid 1960's, just before completing the last installation, he was imprisoned for illegal possession of firearm--which is a grave offense in Japan. (The story writer Hirai and his publisher hired another cartoonist to finish the Eito-man series. However, Hirai was not satisfied with the finished product.) In the 1970's, Kuwata suffered from depression and alcohol dependency. Later, he became a born-again Buddhist. Finally, in the early 1990's Kuwata, who by this time became sober and regained his confidence, finished the very last installation of the Eito-man series.
It is interesting that there is such a dynamic human drama even behind a children's cartoon series. I am glad that Kuwata, a child prodigy who completed his first graphic novel at the age of 13, overcame his alcohol problem and is currently utilizing his awesome talent. Kudos to Jiro Kuwata!! Also, may the soul of Hirai, who died in January of 2015, rest in peace.