The only empire to rival ancient Acheron was the Stygia of old. It survived against that evil kingdom, and Stygia’s past is entwined with the entire history of the world, as if it were the coils of a serpent.
Real-world equivalents: Ancient Egypt crossed with every evil empire from every pulp story you've ever read.
Amen-Ophis, Hapu-Seneb, Harkouf, Hetep-Sekhem, Khephren, Khonsa, Ptah-Hotep, Sa-Nekht, Semer-Teph, Seostris.
Amenakht, Anen, Apophis, Harnakhte, Hemaka, Inarus, Kenamun, Menmet-Ra, Panas, Penamun, Rahotep.
Amendiris, Herit, Itakare, Khamaat, Khnemi, Maatkare, Mereret, Nefertari, Nekhbet, Sekhmet.
Ahwere, Asenath, Henut, Hesepti, Inuhue, Maharet, Senebtisi, Senet, Sitre, Taheret, Timat, Weret.
Conan the Adventurer ch.1, p.24 has a different take on Stygian names.
Core Book ch.8, p.223.
Conan the Adventurer ch.2, p.28.
Conan the Pirate ch.2, p.48 (coastal Stygia).