Couple of interesting passages about Stygian religion. There may be many more, but these two pop into my mind at first.
"Far to the east, the Lemurians, levelled almost to a bestial plane themselves by the brutishness of their slavery, have risen and destroyed their masters. They are savages stalking among the ruins of a strange civilization. The survivors of that civilization, who have escaped the fury of their slaves, have come westward. They fall upon that mysterious pre-human kingdom of the south and overthrow it, substituting their own culture, modified by contact with the older one. The newer kingdom is called Stygia, and remnants of the older nation seemed to have survived, and even been worshipped, after the race as a whole had been destroyed."
—The Hyborian Age
The Cimmerian recoiled, remembering tales he had heard-serpents were sacred to Set, god of Stygia, who men said was himself a serpent. Monsters such as this were kept in the temples of Set, and when they hungered, were allowed to crawl forth into the streets to take what prey they wished. Their ghastly feasts were considered a sacrifice to the scaly god. The Stygians within Conan's sight fell to their knees, men and women, and passively awaited their fate.
—The Hour of the Dragon, Chapter 17 ("He Has Slain the Sacred Son of Set")
Ships did not put unasked into this port, where dusky sorcerers wove awful spells in the murk of sacrificial smoke mounting eternally from blood-stained altars where naked women screamed, and where Set, the Old Serpent, arch-demon of the Hyborians but god of the Stygians, was said to writhe his shining coils among his worshippers.
—Queen of the Black Coast, Chapter 1
I interpret these so that Stygian priests are quite heavily separated from the laymen. Perhaps they live inside the temples of Set. I somehow get the impression they aren't living too ordinary lives, instead, they focus on the black arts and worshiping their god. I vision their lives very ascetic and dedicated to their religion. As Stygia turns out to be a theocracy (even though there's also a royal rulers), I would guess they also have administrative duties.
Nice to see some Howardian quotes, Miikhali!
I think it quite probable that Stygian priests of Set live lives apart from the masses/fellahin. Nothing that REH ever wrote would contradict it. In addition, the priestly castes of Egypt and the Aztec Empire were certainly on a different level than "commoners" (usually slaves, in a Stygian context).
Stygia seems to be a racially-based (semi-)theocracy, with a vigorous caste system. There is the royal family, the priestly and warrior castes AND THEN the commoners/serfs/slaves. Thoth-amon would fit easily into either. One finds a similar stratification in Pharaonic Egypt.
Probably the ordinary Stygians both fear and abhor the priests, but probably they are too afraid to actually hate them. Actually they may greatly honour priests --or at least the cult of Set, as in The Hour of the Dragon-- as they seem to be really brainwashed into Setitism (or whatever you call it). My very uneducated guess is, that children may be sent to the temples to serve as priests, just like in the Middle Ages monks often came from poor families that wanted to assure bread for their children. Starting as novices, they may be able rise to quite high ranks. I find it very improbable that Stygian priests may have any kidn of sexual relationships, so all the priests need to be initiates.
Robert E. Howard provides no evidence that there was "upward mobility" for the poor through the priestly caste in Stygia. Such a caste would be thousands of years old. REH's utterly negative view of Stygia would seem to preclude such an "egalitarian/populist" model.
The priests of Stygia maintained their power through black magic, education (theirs, nobody else's) and propoganda (and well-handled eugenics).
As for the remnants of the elder race, could it be that the Stygian royal family and other noblemen are their descendants? Naturally there would be a lot of Lemurian blood in their veins, but at least they could trace their ancestry to the original inhabitants of Stygia. Perhaps they also serve as the high-priests of Set, honoured as kind of Set's deputies. This is purely a speculation, of course.
I keep seeing the "elder race" in reference to Stygia. Robert E. Howard never, ever made that connection. The two "Elder Racians" we know of from "Tuzun Thune" had violet/grey eyes and were of short stature. That certainly doesn't match up with "high-caste" Stygians described by REH. Karon from the "River Stagus Fragment" was tall, but there's nothing to connect him with Stygia, pre-Cataclysmic or otherwise.
The "original inhabitants" of Stygia (according to REH) were "pre-human". The "Elder Racians" in the Kull yarns were NEVER described by Robert E. Howard in that way.
None of this truly relates to this thread. Two pertinent threads would be this one on Stygia:
..and one on the Elder Race:
I've studied the Elder Race (and REH) for decades. There simply isn't anything to connect them to Stygia. If there WAS, it would be a topic for another thread.