In Eternal Darkness, Darkdream cannot survive under sunlight, and is shown to have some kind of connection with Evil-lyn–she is his ally and it is implied that Darkdream has power over her magic wand.
My take on the character depicts Darkdream having returned after his most recent defeat/banishment. The elements that I added to his costume are colored to emphasise his connection to Evil-Lyn. Here’s just a bit of background info:
With the help of unseen forces of evil, DARKDREAM stalks Eternia once more! He maintains the ability to put his foes to sleep and control their dreams, but now he has manifested a powerful corporeal body as well, possessing strength to rival He-Man’s! Darkdream can no longer be banished by sunlight–though he is still weakened by it. The Master of Nightmares seeks revenge against He-Man, and against his niece Evil-Lyn, who deserted him during his final battle. It remains to be seen whether the Faceless One will choose to intervene in the conflict between his brother Darkdream and his daughter Evil-Lyn.
So there you go, I just decided that Darkdream is The Faceless One‘s brother. Makes sense, right?