User blog comment:Omega natsu2/Chapter 413: The Book of E.N.D., Predictions./@comment-172.56.3.122-20141216004353/@comment-9595671-20141218111411

The one thing I feel makes any possession of a character unlikely is that Igneel fought END and couldn't beat it.

Think about it, if he couldn't beat END then END should still have a body to use just like how the Lullaby had a sealed form as a flute but then turned into a giant tree creature.