This anime was remade in 1991. The remake, a Hong Kong action gorefest, dealt more with Riki's backstory and contained more violence and gore. The remake is now consider a cult classic.
Riki Oh is very similar to Ken from "Fist of The North Star". They both are human beings with the strength of 50 men.
In the live version the warden transforms into an "Incredible Hulk" type creature. He does not transform in this version.