neart_roimh_laige
First of all, it seems that when Returned give their blessing that requires their life, to do so is to give up all of their BioChroma. Well, there was a time where Vivenna can't sense Vasher because he was a drab. Since that would mean he put all of his BioChroma somewhere and is SPOILER one of the Returned, why isn't he dead?
Also, it seems as if only the royal family has the ability to change their hair color. However, when Vasher kills Denth, his hair flashes through a ton of colors before he dies. What are his ties to the family? Is there something I missed? Will there be another book explaining this?
Brandon Sanderson
I did mention these things in the annotations, as has been pointed out, but boy--it's been a while. I don't remember what I wrote in the annotations and what I didn't.
All Returned are, in a way, "related" to the royal family in their Investiture. (The magic they hold.) Vasher has some specific and powerful control over his own powers, which I didn't go into much in the book. But if you delve into the annotations, you'll get more.