Some of you may disagree with me, but think about it... Do any of you have ancestors from another racial group in your family tree? If yes, then you may realize that what I am trying to make a point here.
As people migrate across the world, their children that settled in a region will interbreed with the local people. As a result they bring new genes into the local population. Same with these who leave their homeland and bring back their child from a romance that they had in a foreign land. As a result there ought to be some diversity, like a NPC child who has a mother from Xian Sai and a father from Kurast, or a scholar with Aranoch and Ivorogod blood ties.
and if you want the full picture of multiraciality in America, here's the facts.