Theon

The head bounced off a thick root and rolled. It came up near Greyjoy’s feet. Theon was a lean, dark youth of nineteen who found everything amusing. He laughed, put his boot on the head, and kicked it away. (AGOT Bran I)

I take it to mean that he is dark in every sense. His hair, beard, personality, sense of humor, eyes, manner, and so on. But if his skin is dark I think it’s supposed to be dark only by comparison to other northerners. I like the idea that the darkness extends to his skin too a little bit, giving him a slightly darker complexion than the Starks which sets him apart visually as well as the other ways in which he is apart from them. He’s kind of out of place here in every way, but only just enough to reinforce his feelings of being an outsider. It’s thought that pale skin is adapted for colder climates and dark skin for warmer, so a minor difference in shade can even allude to the idea that Theon doesn’t merely imagine his disadvantages into existence but he’s actually disadvantaged in this place. That makes me think of the Old Gods and direwolves and stuff. Though the magic in this story always feels analogous to real things that are simply intangible or not yet understood, like sociology and spirituality. I’m sure there is probably an aura of Starkness around Winterfell, its people and Theon’s circumstances that feels to Theon like an oppressive force sometimes.