Lancelot was a knight of the Round Table and a Lord of Avalon. He was hopelessly in love with Guinevere, but he never betrayed his liege King Arthur, despite the rumors that he slept with the man's wife.
Elaine of Corbenic was in love with Lancelot, so she made a bargain with Narishka. Narishka would make Elaine irresistible to Lancelot so that she could seduce him; in return, Elaine would conceive and carry a child born of Narishka and Lancelot. Narishka accomplished this by placing one of her ovaries inside Elaine. Unfortunately, the seduction didn't go as Elaine had hoped. Narishka changed Elaine's appearance to make her look like Guinevere, since that was the form hardest for him to resist. Still, he wouldn't have succumbed to temptation if he hadn't also been drugged at dinner. When Elaine realized that Lancelot was attracted not to her, but to their queen, she forced him to marry her lest she reveal his secret.
Their union that ill-fated night produced twins: Galahad (biologically Elaine's) and Varian (biologically Narishka's). Narishka came to collect Varian soon after the boys' birth. She eventually returned him to Avalon, but Lancelot and Elaine both hated and mistreated him.