Lemuria, a powerful kingdom ruled by the Deviants some 22,000 years ago, was a part of the Mu continent. The ruling class of the Deviant empire lived in the City of Toads, the capital of Lemuria. The Deviant empire became a ruthless, worldwide power with Lemuria at the center. The Deviants were opposed by the Eternals who lived in Olympia, Greece.
The Deviants conquered human civilizations with advanced technology and enslaved humanity. Eternals, such as Ikaris and Gilgamesh, sided with humanity against the Deviants' harsh rule. The Deviants became the dominant race while the only significant human kingdom that had the power to oppose Lemuria was Atlantis. The rulers of Lemuria wore the Circlet of the Ascendant.
Around 18,000 B.C., Atra, a human priest who worshiped Set in Lemuria, opposed the Deviant empire and made plans with the Serpent Men, children of Set, to conquer the Deviants. Atra crafted the Serpent Crown as a conduit for Set's power to achieve this goal. The Deviant Emperor Phraug worshiped Set as well and coveted the Serpent Crown.
Phraug ordered that his human army attack Atlantis. King Kamuu, ruler of Atlantis, opened the magma pits of Atlantis, which were the city's main source of heat, to release destructive energies on the invaders. The release of the pits' destructive power caused volcanic eruptions across the region that sank Atlantis.
Atra had begun his attack on Lemuria as the first being to wear the Serpent Crown but Set did not allow his power to be used on his Deviant worshipers. The Second Host of Celestials had arrived during this battle and the Deviants in Lemuria fired on the Celestials' ship. The Celestials attacked Lemuria in response by firing a powerful nuclear weapon that caused shock waves to sink Lemuria. Phraug and Atra both died in the destruction of Lemuria and the Serpent Crown was lost for centuries .
The combination of explosions and eruptions caused the whole continent of Mu to sink into the ocean. The Deviant survivors of what came to be known as the Great Cataclysm moved underground. The southern half of Lemuria had sank underground and the sea had been shut out from this area. Lemuria and the capital, the City of Toads, was re-established as the Deviants' subterranean kingdom.
In the late 20th Century, the Fourth Host of Celestials arrived on Earth and The Deviants attempted to sabotage their arrival which was prevented by the Eternals. One of the Celestials, Eson, unintentionally damaged the underground cavern that contained Lemuria and flooded the kingdom, damaging parts of the City of Toads and Lemuria.
Brother Tode, the Deviants' ruler at the time, ordered construction of New Lemuria beneath New York and the restoration of Lemuria. Thor stopped the construction and New Lemuria was destroyed as a result. The Fourth Host passed judgment in favor of Earth and left the planet. Later, Brother Tode launched an invasion of Olympia and kidnapped the Eternals which all ended in failure.
Brother Tode and most of the ruling class of Deviants were transformed and fused into a giant stone block by the Eternals. The block was taken into space by the Uni-Mind as it left Earth to explore the universe. Lemuria had lost its ruler and most of its high ranking officials. The restoration of Lemuria was finished by the remaining Deviants and Ranar, Brother Tode's son, demanded his right to succeed his father as ruler.
A high ranking lord in the Deviant priesthood, Ghaur, refused Ranar and killed him. Warlord Kro was put into place as the Deviant ruler of Lemuria while Ghaur and the priesthood were the real power in the empire and used Kro as a puppet leader. Ghaur made certain that Kro keep that thought in mind for the future.
The Deviant empire in Lemuria went through different terms of rulers when Ghaur was eventually defeated and apparently slain in battle. Later, Kro stepped down as ruler leaving another Deviant, Visara, to take his place. Visara was later killed in a rebellion against his rule.
Ghaur was resurrected back to life and returned to assume control of Lemuria. Later in Lemuria, Ghaur transferred his consciousness into a statue of himself and captured the Eternals to get information about the Uni-Mind. Ghaur wanted to form a Deviant version of the Uni-Mind that he termed the Anti-Mind. Kro and the Heroes for Hire stopped Ghaur's plans and rescued the Eternals.
Apocalypse launched an attack on Lemuria that caused mutations in the Deviant populace. Amidst the chaos, U.S. troops captured the statue with Ghaur's mind and Ghaur was forced to return to his own body. Afterwards, Kro and Ghaur formed an uneasy alliance where both were forced to share power as rulers of Lemuria.
An international incident occurred between Lemuria and Wakanda when Ghaur's daughter, a Reject (a Deviant with human features), had been given refuge from the Black Panther. Ghaur did not want it known that this girl was his daughter fearing a scandal in Lemuria. Rather than start a war, Ghaur accepted that his daughter and her mother go into hiding in the custody of Namor.
Lemuria has been a lawful and cooperative nation with Brother Kro as a sensible ruler.
The northern half of Lemuria lay on the bottom of the ocean for years before being settled by a group of Atlanteans. Homo mermani had made the undersea continent of Atlantis their home for several hundred years with the Olympian god Neptune as their patron. A group of Atlanteans, who worshiped Set, left Atlantis to form their own kingdom and discovered the northern half of Lemuria. These water breathing people are commonly called Lemurians with similar traits, abilities and physical characteristics as water breathing Atlanteans.
Somewhere around the 15th Century, the undersea kingdom of Lemuria was ruled by an insane tyrant known as Naga who was a devout worshiper of Set. Naga learned from Set that the Serpent Crown was in ancient Lemurian ruins and claimed it in his name. The Serpent Crown imbued Naga with incredible telepathic and destructive powers as well as a reptilian appearance. The presence of the Crown even turned the blue skins of Lemurians into a greenish tint with scales. Set had also revealed to Naga how to treat the Crown with special oils that give its wearer an immortal life.
Naga became deluded and believed himself to be a god who was the son of Set. Naga didn't believe a god should follow any rules or moral code. Anybody Naga considered a traitor or law breaker was killed, tortured or sent to prison. Naga committed acts of inhumane atrocities that became everyday occurrences. The evil reign of Naga lasted for centuries but any civilization ruled by tyranny will fight for freedom. Naga had crushed many rebellions but a group of rebels chose a different tactic in a bid for freedom.
The rebels, later known as the Ancients, had limited telepathic abilities used to hide themselves from Naga's detection but not powerful enough to overcome Naga. The rebels left Lemuria to find a place where Naga could not follow them and formed their own community free of Naga's rule. The rebels also stole the Crown from Naga to be locked away and end its use for evil. Without the Crown, Naga started to age slowly and he formed a group of warriors called Questers led by Karthon. The Questers were ordered to find the Crown and the search went on for decades.
By the early 20th Century, Llyra, a Lemurian mutant, became a high priestess of Set and a close companion to the elderly Naga. Llyra had ambitions of ruling Lemuria and she had manipulated Naga into arranging a marriage between her and his oldest heir, Prince Merro. Karthon the Quester eventually recovered the Crown along with Namor as a prisoner and returned to Lemuria. Naga quickly wore the Crown upon Karthon's return and Namor stood defiant against Naga.
Namor and Naga soon engaged each other in battle while Karthon, observing Namor's nobility and Naga's sadism, was having regrets about serving Naga. Namor was about to be swallowed up by a pit created by Naga when Karthon drew his sword and killed Naga. Namor and Karthon left the Crown on Naga and the creation of the pit caused earthquakes that swallowed Naga and the Crown beneath the ocean floor. Karthon accepted the Lemurians' decision that he become ruler and he vowed to be a proper king. Namor and Karthon, once enemies, continued to be allies.
Several months later, Llyra's elaborate plans, manipulations and ability to control marine life culminated in a takeover of Karthon's throne. Llyra managed to subdue Karthon and claimed the throne. Several days later, Namor arrived in Lemuria to speak with Karthon about the surface world but discovered Llyra ruling the city. Karthon was in chains and Namor engaged Llyra in battle while she sent some deadly sea creatures after Namor. The creatures were defeated by Namor and Llyra was severely injured in a rockslide caused by a sperm whale under her control. Namor freed Karthon and Karthon returned to being king of Lemuria.