Warning: The following contains SPOILERS for Masters of the Universe: Revelation, Part 2.
The first episode of Masters of the Universe: Revelation, Part 2 confirmed a long-teased fan theory regarding Man-At-Arms being Teela's biological father rather than her adoptive father. The episode also confirmed a romantic relationship between Man-At-Arms and Teela Na, the woman who became the most recent Sorceress of Castle Grayskull. This marks the first time that the two elder heroes had been officially linked romantically in any Masters of the Universe reality.
In most variations of Masters of the Universe, Man-At-Arms was presented as the adoptive father of the warrior woman Teela, agreeing to raise her as his own child due to the Sorceress of Grayskull not being able to fulfill her sacred duties and be a mother. Most versions of Masters of the Universe also teased that it was Teela's destiny to become the next Sorceress. Precisely why Man-At-Arms was charged with the task of raising Teela was never really explained, although the 2002 He-Man and the Masters of the Universe series suggested, in the season 2 episode "Out of the Past," that Duncan was an amnesiac soldier whom the Sorceress nursed back to health and came to love. The Sorceress told Man-At-Arms of the soldier who "left me a gift" before he then wandered off to rejoin his fellow warriors. The Sorceress then specifically referred to the gift as "Your child, Teela," leading many to speculate that the Sorceress was being literal and telling Duncan that Teela was his daughter by blood.
Masters of the Universe: Revelation officially confirmed this, with the episode "Cleaved in Twain" opening with a flashback showing a young Man-At-Arms and a woman resembling Teela. The woman was identified as Teela Na, which was the Sorceress' name before she became the Sorceress in the earlier Masters of the Universe cartoons and comics. Teela Na enjoyed one last moment holding her young daughter before stroking Man-At Arm's chin and calling him "My Duncan." She then left them to enter into a secret chamber within Castle Grayskull, where she became bonded to the Power of Grayskull and assumed the mantle of the Sorceress.
Any doubt of a romance between Man-At-Arms and the Sorceress was eliminated later in the episode, when Skeletor (who had claimed the Power of Grayskull in the finale of Masters of the Universe: Revelation Part 1) ran the Sorceress through with the Sword of Power. Man-At-Arms screamed in anguish and ran to the Sorceress's side, taking her into his arms and calling her "my love." As in the earlier scene, she reached up and stroked his chin, once again calling him "my Duncan," before her body was enveloped in light.
Later, in the Masters of the Universe: Revelation episode "Hope, For a Destination," the Sorceress' spirit confirmed her relationship with Duncan while speaking to Teela. The Sorceress explained that she was forced to abandon Teela and Duncan because it was impossible to bond with the Power of Grayskull without being prepared "to give up your life and give up all those who live in that life." Though it pained her to leave behind her family, she feared that Eternia needed her as the Sorceress more than Duncan needed a wife or Teela needed a mother.