User blog comment:LordLuminous/Reviving END: Curse Power Needed? Questions/@comment-5303512-20140727045807

I think that E.N.D. will appear when he takes control of Natsu. Maybe E.N.D. had to find a way to protect himself from Igneel 400 years ago so he had to fuse with baby Natsu.

He wouldn't risk his minions/Tartarus knowing what his current status is so he had to fool them in order to stay undercover from Fairy Tail and Igneel.

E.N.D. Would probably buy his time inside of Natsu preparing to one day exact his revenge on Igneel by using his very "son" and the Fire Dragon Slayer Magic to kill him with.

Though it is true that E.N.D. can only be revived by nullifying all magic, but this brings me back to my Lisanna/E.N.D. Theory (which I no longer using) he would live inside of a Human Mage in order to adapt to the use of Magic and Natsu would be his Ace in the Hole should Face be stopped.

With hosting Natsu, It would be E.N.D.'s ace in the hole/back up plan should Face fail to activate, he would get accustomed to Natsu so when the time either Face activates, he would leave Natsu's body and be resurrected, or if it fails, then he would just take over Natsu's body and take matters into his own hands, because either way, I think he might have his own secret agenda to kill Igneel, either Igneel loses his magic or dies by Fire Dragon Slayer Magic.

Natsu's powers could be amplified if E.N.D. Took control, similar to Brain sealing away Zero, after Zero took control causing his powers amplified.

Maybe E.N.D. thought that Face would make his return and killing Igneel a lot easier, and if it failed then he would resort to killing Igneel the hard way and his return difficult with trying to possess Natsu. As long as I have know Fairy Tail, there is always some hidden agenda and some plot twist that we are not aware of.

Though I am looking forward to Tartarus Arc Part 5: Ultimate Pain, it actually reminds me of Dark Knight Rises.