User blog comment:FairyRaven/Fairy Tail Chapter 365: Fairy in the Jail!, Review and Commentary/@comment-76.121.234.236-20131230020022/@comment-7418318-20131231111032

So he "downloaded" part of himself into Natsu before self-destructing?

While I don't think that's what Mashima is actually doing, it is a great idea. With the way Natsu took little harm from Jackal's earlier explosions once he figured out the "trick" it'd be reasonable for the Demon to assume that Natsu would survive the big boom too. Though obviously Jackal can't have full control, since Natsu first went to Crawford's house rather than straight to Tartarus HQ.