Attuma was born into the tribe of Homo Mermanus who eschewed civilization to live as underwater nomadic barbarians. By some unrecorded method, Attuma was endowed with strength far surpassing that of his people. Nearing adulthood, Attuma learned of a prophecy, in the lost Atlantean Chronicles, of a conqueror who would take the empire of Atlantis by force.
Believing himself to be that conqueror, Attuma moved to a position of leadership over his barbaric brethren, and launched an attack on the city of Atlantis and its ruler, Prince Namor, also known as the Sub-Mariner. Attuma was helped by the betrayal of Lady Dorma, who was seeking revenge for Namor’s dismissal of her love. Dorma then sought rescue for Atlantis and Namor by eliciting help from the hero team Fantastic Four, who, with Namor, ousted Attuma’s troops1.
Attuma turned his attention to conquering the surface world. In his first early attempts, he employed huge engines of destruction, namely the giant transport Robotron (defeated by Wasp and Giant-Man) and the so-called “tidal expander” (defeated by the Avengers). He was among the many menaces assembled by Doctor Doom to disrupt the wedding of Reed Richards and Susan Storm2.
Soon, Attuma returned to invading Atlantis and fighting Namor. His schemes involving stolen alien robots, an alliance with the Atlantean traitor Byrrah, framing Namor for burrowing under Manhattan (thwarted by Namor with help from Stingray and Triton)3, and the creation of Octo-Meks (octopus-shaped fighting machines).
All failed, largely due to Namor’s heroics. Attuma’s early success at ruling Atlantis came when Namor was banished by his countrymen. Attuma and his forces easily moved in, and Attuma sat on the throne only briefly before Namor returned to rescue his city and receive the offer to rule once more.
When Namor abdicated his throne and later joined the hero team Avengers full-time, Attuma convinced Atlanteans that Namor preferred the surface world. Coupled with the fact that Attuma’s hordes helped Atlantis defeat a civil war faction, the Atlanteans agreed to have Attuma and his forces serve as Atlantis’ troops. Attuma quickly seized the advantage to rule Atlantis entirely. Namor was also married to the hero Marrina at the time, and Attuma captured her set a trap for his archenemy. Namor confronted Attuma, who convinced Namor that the Atlanteans preferred Attuma’s rule. Namor returned with the Avengers and Alpha Flight to rescue Marrina and Attuma was left on the throne.
Attuma later joined the Deviant Lord Ghaur in forming an alliance to take over the world through the re-creation of the Serpent Crown. In preparation for this, Attuma led Atlantean and Lemurian armies against the surface world to weaken the United States, in which battle Namor confronted them and appeared to have died.
Months later, Attuma resumed his attack on the surface world, claiming that humans (specifically, a Japanese whaling ship) were disrupting Atlantean food supplies. He was stopped by Namor and his ally Sunfire, and returned to Atlantis, content that he was able to at least destroy the Japanese ship.
Currently, Attuma is back to being a barbarian ruler under the sea.