Four of the five sapient species have widely varying natural skin colours depending on climate. Blood colour also plays a role in determining the exact colour of skin, so all but the darkest climate-variant skin colours still look different depending on species.
Rocca have extraordinarily little variance in skin shade. Since they all live on one continent, the cause of this (intrinsic and/or geographic?) is unknown.
Shade's sapient species are much alike in that they discriminate within their own species, and others, based on skin colour and/or home country, but do not discriminate on the basis of species against anyone of their own country.