User blog comment:IamJakuhoRaikoben/Chapter 503: The Last Sight Seen, Review./@comment-5303512-20160926122525/@comment-1776824-20160926145235

I don't think you read anything that disproves what you are saying. It has been explained that Zeref created the Etherious with a pre-programmed desire to hunt him down and kill him. Mard Geer also reiterated this fact prior to it coming out of Zeref's mouth. The Etherious who are not aware of the exact nature of this feeling call it "returning to Zeref," and are indeed very much devoted to their creator. However, their creator created them to off him, and that is literally what they all tried to do and are devoted to doing. If you have any doubts about this, I redirect you to the entire Tartaros arc.