But perhaps the episode owes more to a Cinderella variant found in several Native American cultures - The Wife of the Invisible Warrior, where the characters find happiness because they can see in each other that which is invisible to everyone else. That's been at the heart of Zeref and Mavis' story for quite some time, but we can also see it with Jellal and Erza. When Jellal this week is shocked to find that he's alive (and possibly a bit disappointed; he really seemed to believe that self-sacrifice would absolve him of his sins), both Erza and Jenny tell him that he's still around because his mission is to live. He did bad things, yes, but it's time to move on, and not in the same way Zeref just did. Erza sees the good in him that he can't see himself.
However, it's too early for us to all sit back and rest on our happy ending laurels just yet. Zeref has gone, Mavis has found happiness, Natsu's apparently been rewritten as a human rather than a demon – oh, wait, did that actually work? At first it seems to have – Lucy's finished using her powers as a writer (a trick a lot of authors use in YA fiction, but somethings are standards because they work and make for rewarding storytelling), Gray used his demon slayer powers to get the residue out from under her skin, and a battered Natsu came home to the fold—for about five minutes. But when Lucy, Gray, and Happy turn back to talk to him, he's gone again. Did the spell Lucy cast not work? If it didn't, it's certainly setting up a parallel between Zeref and Mavis' relationship a century ago, when they were unable to save each other. Is their fate about to play out all over again?
It's an awful thought, no doubt about it, and that enormous crack in the sky Erza and Wendy see is certainly not a good sign. But Makarov was given his life back by Zeref and Mavis, whom he saw as he was booted out of the afterlife, so that's a little piece of hope we can hold on to as possibly having greater significance in terms of what's possible. This may just be the final trial that the protagonists of the fairy tale have to face before their happy ending – and if they can wash the drops of wax out of the shirt to close the hole in the sky, everything may turn out to be all right after all.
We'll just have to hope.
Fairy Tail: Final Season is currently streaming on Crunchyroll.