User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-175.101.10.90-20130809061102/@comment-86.40.11.52-20130811160134

I agree with most of what you said especially about zeref and achnologia being linked and defeating one of them will severely weaken the other. But what if it's actually natsu and achnolgia that are brothers, therefore zeref believes natsu has the potential to surpass achnologia, so zeref helped send him and the others to a different time knowing that if he stayed in the current time(past) achnolgia would of killed them.