So, I remember when I was little there was this anime where the main male character had purple hair. He, for some reason out of his control, turned evil and when he did he had dark blue hair. Long hair, if it helps. I think he might've been a prince or had some sort of armor. Also, this would have to be animation like the one that was around the 90s.
I know this isn't much but god, has this been eating at my