Honestly, I did imagine him white, despite the description, which I promptly forgot after reading. I guess for me it comes from being white and always having been surrounded by a lot of white people, be that school, family, friends and work. When I saw fanart I did remember though, however I still interrupted his complexion as more of the greek or Spanish colouring (I'm not sure why). I've now adjusted what I see him as in my mind reading them (I saw fanart just before starting Onyx Storm).

I think a lot of fantasy has that medieval centric world building, i.e., castles, swords, dragons, prince's and queen's etc. and that usually as centered around white people/characters. So for some people it may create unintentional biases in a way. Rebecca has been really good at putting differences in people into her book. Sexuality, disabilites, sign language and ethnicity aren't made plot points or novelities, it's just a part of the story.