dug even further into the dirt and came up with another called "Phthon"

Exposing to all and sundry my dilettantish (I'd say encyclopedic, but tsuwm may, to his sadness, trump me here) knowledge of bad sci-fi, I believe the sequel to "Chthon" was called "Phthor," from some superficial resemblance of the main character to the Norse Thunderer.