Thread:SpiritedDreaming/@comment-24857712-20150927024310/@comment-26397825-20150929203116

Ren technically goes by his last name if he follows standard naming traditions. And since everyone else does, and the cultures of today don't exist in Remnant which is why Yang's name is not "Long Xiao Yang" or something similar, it is within reason to assume Ren goes by his last name. Some people do that.