Aurora says it better than I, but I must say it too. This book was pretty fantastic, for as much as it dragged in many parts.
Tezuka holds off but all but the most basic of fantasy elements, and devotes his attention primarily to the failures and triumphs of the human spirit. There are some brief flirtations with Western religion, lots of good suspense and overlapping plots , and a sound argument that power corrupts and adversity brings true strength of character. And I bought it. It brings together some of the better doctor themes of Blackjack with the existential questions of his more SciFiy-stuff. And Tezuka brings some great emotionally expressive portraiture to this book that I am sure influenced later folks like Dan Clowes heavily. And he does it better, of course.
Plus as a bonus, I watched the Cove and learned about Minimata disease, a condition that arose from wastewater consumption in rural Japan, which the Japanese government did little to stop and apparently tried to cover up. Art imitating life perhaps a bit here? Wild.