User blog comment:Baluar/Arc 3, chapter 5/@comment-10225593-20150323145014/@comment-25977712-20150324122420

My guess would be that most God Arcs were once Human but their souls and thoughts transfered into the Aragami's mind. Supporting my guess is that God Arcs are also Aragami so they could be anything. Ren originated from Lindow's mind(or so I thought), makes him special than the others.