In the days of when King Arthur held the throne of Camelot, Morgaine Le Fay, disguised as a human, began a relationship with one of his knights, Jason Blood. However, she had sinister plans in store for Camelot, and later fought Etrigan and Shining Knight. Morgaine gives Jason the "viper's kiss".Morgaine and her army of monsters attacked King Arthur's castle in an attempt to place her only son Mordred on the throne. Arthur's forces held out against the invading army. However, Jason Blood betrayed Camelot for his love and allowed Morgaine and her army to storm the castle. She returned the favor by poisoning Jason Blood with a viper's kiss. Camelot fell that day due to Le Fay's invasion. However, she would not, or possibly could not, place her son on the throne without the legendary artifact known as the Philosopher's Stone. The wizard Merlin hid the artifact in an arc. Morgaine and her spell allowed her and her son to live for eternity. Though while Mordred would continue to stay young, she would be forced to find young men and women to drain their youth from. The warning brooch.For centuries, Morgaine and her son searched the world for the Philosopher's Stone all the while being pursued by the demon Etrigan, who became bound to Jason Blood after Morgaine's supposed fatal kiss. Fortunately for Le Fay, she kept a brooch that glowed whenever he approached.Morgaine and her son finally found where it was hidden from a librarian in Gotham City. The duo traveled to Castle Branek only to discover Merlin's arc empty. Morgaine and Mordred realized that one of the archaeologists who excavated Castle Branek must have taken the stone for themselves. At that same time, Etrigan had recruited the Justice League for assistance. J'onn J'onzz attempted to locate Le Fay with his telepathy. However, her sorcery overpowered his telepathic skills and he became bound to Le Fay, constantly being tormented with visions of his homeworld being restored by Le Fay. After being attacked by Etrigan, Batman and J'onn at one of the archaeologists home, she fled to the other during a Halloween party. Finally, Morgaine found the Philosopher's Stone. As Morgaine reached out for it, Wonder Woman pulled it back and kept it. Morgaine turned the party's host, Harv Hickman into a giant worm creature to deal with the Amazon Princess. As she fought the beast, Morgaine again attempted to grab the Stone only to be hit in the back by Etrigan. The opportunity allowed for Wonder Woman to escape with the stone. Morgaine, enraged, blew the playboy mansion into splinters. Now Morgaine was prepared to use the Martian to get the Stone for her. After sending her army of monsters to the Watchtower, J'onn could not stand it anymore and took the Philosopher's Stone. With the knowledge that the stone would soon be in her grasp, Morgaine turned London into a kingdom for her Mordred. J'onn brought the Stone to Le Fay but he was stopped by the Justice League. Morgaine and Mordred defeated Batman, Wonder Woman and Flash. J'onn saw into Etrigan's mind while fighting him and saw her betrayal at Camelot centuries ago; J'onn crushed the Philosopher's Stone after coming to realize that he was being duped. Morgaine announced that they may have lost the battle but not the war. With the Philosopher's Stone gone, Morgaine and Mordred searched for other means to place Mordred on the throne, while the would-be king grew steadily impatient. Morgaine and Mordred finally managed to find a charm that would place Mordred on the throne — the Amulet of First Magic. Mordred took the amulet for himself and cast his mother aside, banishing her and all adults to another dimension. Morgaine managed to find the Justice League and request for their assistance against Mordred. She transformed Superman, Wonder Woman, Batman and John Stewart into children to fight her son. The Justice League succeeded by tricking Mordred into becoming an adult himself and thus banishing himself. The world became free of Mordred's influence and all adults were returned. Morgaine kept her end of the bargain with the Justice League and turned them into their former selves again. She left with her older son to their home in an unknown castle. Mordred's transformation into an adult cost him his eternal youth and all the years that this kept him from ageing caught up with him leaving him an old man who could only grow older, though he would live forever under the care of his mother.
The son of Morgaine Le Fey, Mordred is sustained by his mother's magic, leaving him in the form of a child despite being centuries-old. He agreed to this pact because of his mother's promise to secure him Camelot, but grew steadily more frustrated as the years went by with no success.In the 21st century, Mordred's patience reached its limit, and he betrayed his mother after they found the Amulet of First Magic. Taking the mystical artifact for himself, he declared that no one would tell him what to do anymore and altered reality, banishing all the adults to an alternate dimension. After this, Mordred began reshaping the world to his liking, transforming an amusement park into a nightmarish medieval fortress and allowing the children within it to run free and act as they wished. However, the young king found his rule challenged by Batman, Green Lantern, Superman, and Wonder Woman, all transformed into children by Morgaine Le Fay to exploit a loophole in Mordred's adult-banishing enchantment. After his attempt to execute them failed when Wonder Woman tamed a baby Etrigan, Mordred personally attacked the heroes when their attempt to steal his amulet went wrong. He used his augmented powers to pursue the Justice Kids, eventually increasing his size and manifesting weapons and a suit of armor to battle John Stewart's enormous robot construct. Although Mordred gained the upper hand against the Green Lantern, the distraction gave the pint-sized League the chance they needed to steal the Amulet of First Magic. Etrigan promptly destroyed it with a bite, but Mordred's power remained; he smugly revealed that he had already absorbed most of the amulet's power into himself. Suspending his foes upside down in the air and transforming a nearby prop into a large sword, Mordred prepared to finish the heroes off. However, the young would-be-ruler was be interrupted by a little girl, crying for her mother. Irritated by her cries, Mordred tried to assure the girl that she didn't need her mother, to little effect. His incompetence caused Batman and John Stewart to mock the "king", with the former sneering that Mordred was still just a little kid beneath all of his power. Infuriated by the taunts, Mordred magically aged himself to adulthood - which was exactly what Batman had hoped for. The act caused Mordred to fall victim to his own spell, dragging him into the pocket dimension with all the other adults. Moreover, aging himself broke the magic which had kept him eternally young, but not that which gave him eternal life. Consequently, Mordred's body had aged into a form fitting his centuries-old life, reducing him to a powerless, extremely elderly immortal, remaining in the care of his doting mother.