I'm going to throw it out there, but fair skin for centuries in Japan has been considered a sign of beauty, I think we are talking as far back at 10th century AD. If I were to hazard a guess, if it was an artist deliberately doing it, I don't think the intention is racially motivated or an attempt to white wash a character. Japanese characters are so often depicted by the Japanese as having fairer skin than Japanese people tend to in the real world. It could well be because of this cultural difference.