User blog comment:Xilinoc/Ch. 570 (I can't think of a witty title at 11 pm)/@comment-29183117-20140226133717/@comment-29183117-20140226153337

That would explain why there are Quincy with Japanese names and others with European-sounding names. There being Quincy in every part of the world would explain how the Shinigami were unable to kill them all, and why some of the Sternritter (ie, As) have names that seem Germanic in origin, while others (ie, Mask or Cang) have names that are non-German, yet are not Japanese either.