The Lemurians are a branch of Homo mermanus that migrated to the Pacific Ocean and settled in the ruins of the Deviant city called Lemuria, after it was sank by the Celestials.
The Lemurians are set apart from their Atlantic relations by the discovery or development of the Serpent Crown, an artifact of ancient power that places the user in mystic contact with Set, an snake-like elder demon. Veneration of this crown and its use in rulership has made their skin greenish and scaly. It has also given them a greater potential to wield magic.
The Lemurians are currently ruled by Llyra. For over 500 years Lemuria was ruled over by Naga, who stayed young due to the effects of the Serpent Crown. He was killed by Karthon the Quester for killing Karthon's sister Lyana. It was presumed Karthon would lead Lemuria after Naga, but his reign was a short one. Namor eventually learned that Llyra had inherited the kingdom from Naga's son Merro after she poisoned him.