Happy felt each one of Zeref's words like a physical blow. How could any of this be true? How could Natsu be E.N.D.? Natsu, his best friend, the one who was always fighting against the darkness, who never gave up on what was right... a demon? It just didn't make sense. Zeref had to be lying.

And yet, when he put the pieces together in his mind... they fit.

The Battle of Fairy Tail, when Natsu couldn't pass through Laxus' age-restriction barrier. Tenrou Island, during the S-Class Trials, when Zeref seemed to know him.

It couldn't be true... could it?

Demon or human, he was still Natsu. And Natsu was Happy's best friend. He couldn't let him die, even if his sacrifice would stop Zeref. There has to be another way!

Happy's wings and paws moved of their own accord, swooping down and grabbing the dragonslayer before he could land what would be the final blow for both brothers. He knew Natsu would be mad, but wouldn't he have done the same for any of his friends? The Exceed could never forgive himself if he let Natsu end it this way. And what about the rest of the guild? Hadn't they always preached the power of friendship and teamwork? They could all figure this out together and defeat Zeref without losing anyone.

And then there was that thing Natsu wanted to take care of after the final battle. Happy had known what it was long before Natsu did, and he'd spent far too long helping his friend realise his own feelings and gather the courage to say it out loud; he couldn't let him die before he said it to the person who needed to hear it the most. He couldn't make her live with that heartache.

Natsu was quiet the whole flight back to the guild, leaving Happy alone with his thoughts. Zeref was a despicable being, overflowing with destruction and dark power, and yet... Happy understood where he was coming from. Zeref had been so desperate, so relentless in his desire to bring his baby brother back from the dead, that he had ended up creating the Etherious. He was willing to do anything for Natsu, just as Happy was. While he would never be able to forgive the dark wizard for all the evil he brought into the world, Happy found himself silently thanking Zeref for not giving up on Natsu. He knew the dragonslayer would be blaming himself for everything and expecting to be hated by the rest of the guild once they learned the truth. The Exceed could only hope that once they returned to Fairy Tail, Natsu would see just how much everyone cared for him, no matter the circumstances. Sure, they were likely to need a little time to come to terms with everything, especially Wendy and Gajeel, but if there was anything Happy learned from his life as a Fairy Tail wizard, it was that you never give up on your friends.

As the sun started to set and the Magnolia skyline came into view, Happy tightened his grip on Natsu's vest and made a silent vow to his friend. You don't have to solve this on your own, Natsu. We're gonna do this together.