Xaltotun was the high priest of Set 3,000 years before Conan's time. He was an Acheronian. That's what I know is for sure. The priests of Set are necromancers. Here is what Xaltotun said about his priestly rites,
"Aye! Many a barbarian, both man and woman died screaming on the alter under this hand. I have seen their heads piled to make a pyramid in the great square in Python when the kings returned from the west with their spoils and naked captives."
I think Set was the chief god. I don't know, but many of the Egyptian gods such as Bast the cat goddess, Isis the goddess of magic (I think she was said to be a goddess of Shem), Anubis the god of the dead, Thoth the god of knowledge (may be were Thoth Amon's name comes from). There are many others, but these I like best.
I hope that helps a little.