User blog comment:Lord Zeref Dragneel/Top 25 most powerful characters/@comment-25111584-20150812160455/@comment-1153699-20150813014554

Minerva and Kagura (and many other characters) didn't leave their guilds for a year to train their asses off every single day to prepare for Acnologia / END / Zeref.

So I agree they shouldn't be anywhere near even the likes of Natsu and Gray (and possibly Gajeel) based on what we've seen from everyone so far.