I’m thinking about using the ancient Levant, Egypt and Mesopotamia as inspiration to the Human city-states of this setting (while the more civilizaed of the Lizardmen will have Mesoamerican inspiration). This does fit very well with sword and sorcery. Both sword&sandal and sword&sorcery go hand-in-hand with this ancient world of city-states, commerce, vengeful gods and towering ziggurats.
This setting’s equivalent of ACKS’ Zahar would be an Egyptian-style kingdom with pyramids, undead and huge opulence coupled with enormous stagnation. Now all that remains of them are tombs to loot, guarded by undead!
The setting’s history goes roughly like this:
First were the Serpentmen, who worshipped terrible Cthonic gods. They made the Lizardmen as slaves by crossing their own blood with that of giant lizards. Then the Lizardmen, led by a messiah of a new, Lawful goddess, rebelled, smashed their old rulers, and built a sprawling civilization in the tropical south.
But then came Men, from across the sky, and their arrival upon a shooting star shattered the Lizardmen Empire. Men also arrived in bad shape, and, at first, regressed to savage nomadism, sometimes used as slaves or mercenaries by the Lizardmen city-states which rose after of the Great Cataclysm. But some Lizardmen and many men, without the guidance of the old Lizard Empire’s Matriarch, turned back to the Serpentmen’s dead gods, and their bloody rituals.
Out of the chaos then rose the great Empire of Man, upon the River of the Desert, worshipping Chaotic gods from beyond the grave and investing their resources in their immortal dead kings much more than in their living subjects. But the empire, after a millennium, eventually stagnated and fell back into barbarism, leaving behind ruined temple-yards and ancient tombs filled with gold and peril.
Finally, in the more temperate North, beyond the Great Desert and its River, tribes once subjugated by the Empire of Man won their freedom, establishing their city-states. Some worship the Lawful gods of Man, while others pay homage to the blood-soaked idols of the long-dead Lizardmen.