Chthon

Blurb

Chthon is a science fiction novel by Piers Anthony, originally released in 1967. It was Anthony's first published novel, and was nominated for both the Nebula Award for Best Novel in 1967 and the Hugo Award for Best Novel in 1968.
Its sequel is Phthor and two additional novels in the series were written by Charles Platt: Plasm and Soma.