Lastly, though it would be hazardous to strain this point, we find in his chief impersonations a chthonian character, a touch of the mystery that is shrouded in the world beyond the grave.
"Sketches and Studies in Italy and Greece, Vol III."
John Symonds
A man who divorced his wife was to make an offering to the chthonian gods.
"Plutarch's Lives, Volume I (of 4)"
Plutarch
You go to the chthonian folk for guidance because they are themselves the Oldest of the Old Ones, and they know the real custom: they know what is Presbiston, what is Themis.
"Five Stages of Greek Religion"
Gilbert Murray