User blog comment:IamJakuhoRaikoben/Chapter 503: The Last Sight Seen, Review./@comment-5303512-20160926122525/@comment-5303512-20160926150338

That does not mean anything, yes they are created with the instinct to kill Zeref, it can be interpreted however they like it can still the basis of their faith, just as God created man with free will, that too is the basis of humans faith. However, END is not like them in that regard, he is going to kill Zeref by his programming' but it looks like he will do it out of hatred not devotion.