
(Spoilers Extended) Just stumbled upon Night's King having an origin episode all the way in Season 2 on the History&Lore mini-series included on the blu-ray release.
Never knew these existed and I just stumbled upon the transcript of a very interesting episode about Night's King from Season 2.
>Ygritte: "Swords in the darkness." Aye. The black brothers of the Night's Watch are that at least, as too many of the Free Folk know.
You Southerners are strange. A man murders and you train him to kill better. A man thieves or rapes and you send him where it's dark and private.
Well, at least you make him promise to be good and then you make him regret even that.
From the time he's woken to the time he's allowed to sleep, he walks the frozen wall, carries frozen stones, or boils frozen food. When he lies down at night, he can't have anybody to warm his frozen bed.
Well, not unless the crows like to "nest" together.
You think he remembers the stories they told him then? About when the White Walkers woke in the Land of Always Winter and how the Wall and the Night's Watch were raised to stop them the next time? Never mind trapping us on the other side?
We Free Folk have our stories, too. About how one of your king crows found something cold in the woods with bright blue eyes. How he brought her home, through your wall, and declared himself "Night's King."
For thirteen years, he and his queen ruled over his brothers, making sacrifices as black as their cloaks. Lucky for you Southerners, the Free Folk rallied to a King-Beyond-the-Wall, as we will when need be, and marched on the ancient castle he had taken as his own, the Nightfort.
With the help of the Starks, we killed the demon and cleansed your precious watch. And then they thanked us and kicked us back across the Wall. As you always have.
Gendel, Raymun Redbeard, the Horned Lord. Each chosen as a king-beyond-the-wall, each promising victory. And all fallen to the Night's Watch and the Starks.
But this time it's different. Our new king knows your tricks. You called him a brother crow once, but you never forgot his wings.
We know how you think. We know where you're weak. Watch for us from your Wall if you like. With the cold, you won't even feel the blade slip into your back.
The episode is titled "The Night's Watch" and it is narrated by Ygritte in-character.
I think it's interesting that they chose to include a (mostly) lore-accurate version about Night's King all the way in 2013 where he was clearly depicted as a character seperated from the original Long Night.
Whether the Free Folk originally ended up on their side of the Wall (and then again after allying with the Stark of Winterfell to defeat Night's King so that the Watch can resume their original duty) of their own will or not is left ambigious in the books, but them being depicted as having been "tricked" may be due to the story being narrated in-character, with Ygritte having a certain grudge against Southerners being part of her character.
Another, much more major thing, is that the visuals of said episode clearly depict the corpse queen as an Other (much more ambigious in the books I feel), with Night's "King" being more of a puppet next to her throne. While Ygritte is talking about "sacrifices as black as their cloaks", we also see an unfortunate (possibly naked?) woman tied to her throne. When Ygritte talks about the alliance vanquishing the "demon" and "cleansing" the Night's Watch, we see the queen being impaled by King Brandon wielding a huge greatsword (Ice?) as the colour drains from her eyes, with (probably) Night's King stabbed body lying in the distance.
Ygritte also 'confirms' that the Night's Watch and the Wall were built for an anticipated return of the Others, and that originally they "woke" in the Lands of Always Winter (without a reason being stated), with the visuals depicting them as violently breaking out of some kind of ice-encasement. None of this is unlikely but it also isn't confirmed in the books.
Meanwhile the corpse queen is depicted as still being sealed in ice until Night's King finds her (the visuals and narration kinda remind me of Minerva from Final Fantasy 7), with her eyes only turning blue as he approaches (as if she was still asleep before or 'inactive' inside her ice-encasement).
Some very interesting stuff I think, because it's from very early on and they ended up almost retconning the entire character anyways in the end without ever including his corpse queen at all, who plays an even more central role in the backstory they had about Night's King when compared to the books.