[quote=@Undying Curiosity]
[@Cenco] In the OP it would explain that each color has a specific characteristic, with the exception of black & white.
It seems like you have a character in mind that involves shapeshifting. Instead of an [i]unknown[/i] color, you could have your duel avatar color be either black or white, seeing as they dont have any specific characteristics.

Being a black/white avatar, opens the posibilities to have unique traits(such as shapeshifting). 

[/quote]

Well in canon it seems that shapeshifting abilities default to red for some reason that they never explain in the novels. Unlucky. Then again these are mostly animal shapeshifting so that is probably a prerequisite.