Mrrungo-Mu, better known as the Enslaver, is an alien supervillain from Marvel comics and the leader of a race that are also known as the Enslavers.
The race that would become the Enslavers once dwelled on a dying planet. Mrrungo-Mu, whose inherent great power is of unknown origin, led his people to conquer and enslave others, draining their victims power to supplement their own, thus enabling them to conquer and enslave greater and greater numbers. By this means, Mu saved his race from extinction.
Initially he did what he did to save his people; however, eventually the savagery needed to accomplish his goals, as well as his lust for ever greater levels of power, drove him mad.
Led by the power of Mrrungo-Mu, the Enslavers conquered world after world. Prisoners of the Enslavers were hooked into machinery that constantly transmitted their power to Mrrungo-Mu and to the Enslavers' starship. After the energies of the captives were exhausted, their corpses served as nourishment to Mu's monstrous royal pets.
Mu possessed a large harem, but he kept Tnneya as his chosen woman. However, despite his vast physical and military power, and the immense wealth he showered upon her, she hated what he had become, and she denied him her affections, as she sought two things he no longer understood: love and tenderness.
The Enslavers arrived, causing Galactus problems in finding suitable planets to consume.
The Enslavers conquered Zenn-La, enslaving its populace. Shalla Bal was chosen to be amongst Mrrungo-Mu's harem.
Voyager III, the space probe sent from Earth years before, was launched an unknown distance at great speed by Galactus. It approached and was pulled via tractor beam into the Enslavers' ship. From this, the ship's scientists deciphered the Earthly message of peace and then used its long-range scanners to locate Earth. They transmitted a message discussing friendly contact, which was ecstatically received by Voyager's designer, astrophysicist Earl Weygand. However, while Weygand excitedly discussed the message on television, the Enslavers' soldiers struck, ambushing and capturing the super-heroes and super-villains of Earth. To prove his power, Mu released a group of heroes—Colossus, Doc Samson, Hulk, Namor, Rogue, She-Hulk, Silver Surfer, Thing, Thor, and Wolverine—and then easily incapacitated the lot of them.
Despite these recent additions, Mu's elder engineer Kalldin-Zo pointed out that their massive ship required greater amounts of energy, energy that could only be provided by capturing greater numbers of slaves. Mu vowed to continue conquering worlds and taking ever more slaves, but he warned Zo that he would die most painfully if the power stopped. Mu visited Tnneya, who continued to deny her affections. Pushed to the limit, Mu teleported away, telling her that when he returned, she would welcome him properly.
Tnneya fled the Enslavers' ship in her private yacht as Mu surveyed a new group of dancers, which included Shalla Bal, whose free will and emotion Mu began draining. Mu was furious upon learning of Tnneya's departure, commanding the deaths of both the flight master and the one who brought the message and then ordering that Tnneya be safely returned. The Silver Surfer, who had been investigating a vision of the Zenn-Lavian's enslavement, came across the fleeing craft of Tnneya and rescued her, disabling the ship pursuing her. The grateful Tnneya was strongly attracted to the Surfer, and she took the form of Shalla Bal, seducing him. After some...romance, the Surfer realized that Tnneya was not Shalla Bal, and she returned to her true form, exclaiming his strength in spirit and love, but expressing sadness that Mrrungo-Mu would destroy him. The Surfer disregarded her warnings of Mu's power and convinced her to direct him the Enslavers. Upon learning that Mu was targeting Earth, he took Tnneya and accessed warp space to confront the Enslavers as soon as possible.
Meanwhile, the Enslavers sent crafts to Earth, using giant suction devices to capture and enslave the whole population who were then placed in individual life support capsules and stored in gigantic holding chambers, to be preserved until needed. Mu took up temporary residence in the United Nations Building, and he summoned Earl Wygand, thanking him for leading him to Earth and granting him the reward of one week of freedom. Mu's advisors soon warned him of the Surfer's approach; intrigued by the prospect of testing the power of Galactus, Mu had a laser beacon sent to guide the Surfer directly to him. Mu mocked the Surfer, who struck out at Mu's soldiers, but Mu stopped the fight and ordered all others from the room that he might battle the Surfer unmolested. As the others left, the Surfer—having learned of Mu's power plant from Tnneya—transferred half of his power to Weygang, along with the message to use this power to disable the Enslavers power batteries.
Knowing that with half of his power he could not hope to stand up to Mu, the Surfer nonetheless fought back with all of his might. Mu toyed with the Surfer, concluding that since the Surfer was such a small challenge to him that Galactus must be his inferior as well. However, Weygand managed to destroy the shields around the power plant at the cost of his own life. As Weygand died, the Surfer's full power returned, and he fired a beam into the Enslavers' ship that destroyed the power plant. Though still mighty even without the power channeled from his ship, Mu proved inferior to the Surfer's Power Cosmic, and the Surfer defeated him and then prepared to execute him for his crimes. Tnneya rushed to Mu's defense, revealing that he was a man of unbounded courage and fiery passion, discussing how he had become the Enslaver, and proclaiming her love for him. Moved by her words, the Surfer sent Mu and Tnneya back to their ship, which departed, leaving behind its captives and power cells—never to menace the galaxies again.
The Surfer cosmically restructured the Enslavers' former Power Plant and containment facilities to form a massive armada of ships, which he and Shalla led to return to their lost worlds.