In the manga, there are characters from Xing, a nation existing beyond the eastern desert. Characters from Xing are drawn with much more distinctively Asian features and are identified as foreigners with many cultural and physical differences. I'm sure blackmage_nuke meant that until the characters from Xing were introduced, he assumed everyone was supposed to be Asian, but then got confused when an ethnic group clearly modeled off of the Asians showed up and were treated as strange foreigners by the main cast he had previously considered Asian.