I’ve been thinking about the Night King and why the showrunners decided to create a supervillain out of the amorphous, faceless, eldritch evil that the Others are in the books.
One reason, as I suspected early on when I saw Hardhome, was the need individualize and narrow down the threat to a classic Protagonist VS Antagonist formula, for dramatic purposes. Instead of facing an impersonal evil, Jon, the champion of the Night’s Watch (and by extension humanity) is directly antagonised by the Night King---the champion of darkness. A bit of a Evil Wizard archetype, a bit of a demigod à la Sauron---the NK is someone who, albeit silent, has a degree of characterization, a personality (we can easily infer he’s smug, he’s ambitious, he’s single-minded, he toys with our heroes in a mocking way, he used to be a human being until the CotF turned him into a magical creature with unlimited powers; he even has flaws that we can conceptualize as human). It’s the bare minimum of characterization but it’s still a characterization, and it’s both a positive and a negative thing. Positive because it gives the audience something to latch on, a Villain With A Face and, to a degree, even a motivation---negative because it undermines the sheer eldritch horror of the Others being quintessentially inhuman in every possible way.
The other reason is probably because d&d needed to give the White Walkers an Achilles’ Heel so that our heroes could defeat them---all of them. I think the Others will have an Achilles’ Heel in the books too (maybe whatever lies beyond the Curtain of Light?), but perhaps either GRRM still didn’t know what it would be when he sat down and talked about the endgame with the showrunners, or GRRM’s version of it is something d&d couldn’t do on the show for budget and/or time limitations, so they had to come up with an alternative or a shorthand for it. Either way, it’s food for speculation.
I’ve already talked in favor of Arya, and not Jon, being the one who killed the NK. While I’ve seen people warm up to the fact that this totally makes sense for Arya’s arc, many still resist the idea for what it supposedly does to Jon’s arc. What about the Azor Ahai prophecy? What is the significance of his arc now? What was the point of building up this one-on-one antagonism between him and the NK if Jon didn’t actually defeat him? Well, imo the idea behind this decision wasn’t shock value for shock value’s sake, but rather an attempt---I won’t argue if successful or not---to subvert the Chosen One trope, almost Tolkien-style, in the sense that the chosen one gets so, so close to complete his mission yet ultimately, tragically, fails. But the... small metallic object... is still delivered in the right place to destroy the Evil Overlord and his entire army, and the person who does is an unexpected one, in an unexpected way. So the bittersweetness of this anticlimax, the way it feels both right and wrong, is probably intentional---because the Chosen One(s) both won and failed. Jon and Dany will likely be remembered as the heroes, the Azor Ahai’s, the great commanders, the princes that were promised, but they know deep in their hearts that, had it been for them, humanity would have been destroyed.
speaking of Tolkien, and looking at it from another angle, the last moments of the battle did remind me a bit of RotK in the way Bran (and according to some interpretations of the scene, Jon too) kept *the eye of Sauron* distracted so Arya/Frodo could get close enough without being noticed. Not only them---the entire battle can be seen as a giant distraction game to blindside the NK and take him off guard.
all of this will, of COURSE, play completely differently in the books. But if there’s anything in all of this that can put us on the right track in our book speculation (and imo there is---remember, GRRM talked about the books’ ending in broad strokes with d&d, they didn’t entirely come with this on their own), it would be useful to take a step back and try to see the bigger picture, the most basic gist of it, rather than the flaws of the execution. I think it’s reasonable to expect a degree of subversion of the chosen one narrative, bittersweet tolkien vibes, and the Others being defeated in some sort of anticlimax in the books too.