ML Gets White, Silver or Blue Hair (Wuxia / Xianxia)

White at the end

White at the end

White at the end

White at the end

Blue for most of the drama

Silver on a few occasions, but not the end

Temporarily silver with a bit of red. 

Temporarily silver-y

ML's hair is usually black but sometimes temporarily turns partly silver or completely white. 

Fake white hair in episode 6

Honourable mention: Xiang Liu (generally considered the third male lead, but the ML of this drama for me...) starts the drama with white / silver hair but he has an alternate persona with black hair that he uses for part of the drama.