User blog comment:Stone Roger/Natsu and Zeref have somekind of relation?/@comment-104.35.115.52-20141229053511/@comment-76.98.150.103-20150114031935

Igneel was half dead. The other dragons explain that they had pretty much a little amount of strength compared to the strength they had being fully alive. So Igneel and Zeref could have fought and tied considering Analogia beat Igneel when he had almost no power so that does not really say much about Analogia's strength.