This old theory has gained new life after Sunday's episode, which saw the Night King mirroring one of Bran's vision strolls through the snow, with both wearing almost identical outfits. It's been proven time and time again on this show that the costumes on this show are never just clothes — they're filled with as many clues to character motivations and the plot to come as any piece of dialogue or action — so this is definitely nothing to brush off lightly as a mere coincidence.
This "who wore it best?" moment was only the latest in a series of potential hints that Bran could possibly be the man with the ice horns, with the theory positing that Bran will eventually use his powers to travel back in time to stop the White Walkers only to accidentally become the Night King himself.
While the explanation for how this could occur is complicated and relies heavily on the (cop out) of time travel, it would also be an easy way to answer some of the nagging questions fans had about the battle at the frozen lake, specifically how the hell did The Night King know to bring a bunch of big ol' chains to a battle?! If Bran does turn out to be the Night King, that would mean the Night King has greensight — the ability to see the future, past or present but distant events in dreams — and therefore would have been able to know Daenerys (Emilia Clarke) would intervene, prompting the Night King to come prepared to kill a dragon and raise its corpse from the depths of the lake.
Bran being the Night King could also explain the recently introduced "vampire rule:" that if you kill a White Walker, you also kill all the wights it sired. There are many ways this could be explained through magic and lore, but one popular theory is that the White Walkers are using some form of warging to reanimate the corpses — a power we know Bran has access to.
Bran being the Night King would be incredibly bittersweet if true, seeing as the series would then likely end with his brother Jon (Kit Harington) having to kill Bran to save the realm. However, it would also be confusing as all hell for many viewers. Just think how little fans still concretely understand about what happened with Wylis/Hodor when Bran broke his brain!
That's why Bran being the Night King is far less likely than the notion that Bran and the Night King are intrinsically linked like another famous magic duo: Voldemort and Harry Potter.
It all makes perfect sense, really. The Night King marked Bran in his vision similarly to how He Who Must Not Be Named marked Harry when he gave him the lightning bolt scar, creating a connection between Bran and the Night King that can likely only be broken by one of their deaths. (Though we haven't heard any prophecy declaring "neither can live while the other survives" in Game of Thrones, I seriously doubt we'll see both Bran and The Night King survive this entire series. It's basic narrative math.)
So rather than ask whether Bran is The Night King, maybe we should be asking a different question: Is Bran Harry Potter? And if you ask me, it's looking highly probable.
Is Bran the Chosen One? Yes! Although Jon and Daenerys are both speculated to be The Prince Who Must be Promised, Bran is also fated to play an important role in this war as the Three-Eyed Raven — a calling he didn't necessarily choose, per se, but one that was thrust upon him by the visions he received.
Was he tutored by a kindly old British man who died in order for Bran to survive? Yes! The original Three-Eyed Raven was totally the Dumbledore of Westeros. We bet he even had some lemon drops hidden away in his cave.
Is he a bit of a dick? 100 percent! Just like Harry, Bran hasn't handled his calling with grace and humility. Unlike his predecessor, who was patient and kind, Bran has used his being the Three-Eyed Raven as an excuse to treat people, including his sisters, like complete garbage.
Wright has previously hinted that Jon being a Targaryen may be a red herring, and maybe Jon and Dany's fated importance is too. We've been so busy deciphering which Targaryen is going to be the prophesied hero who will save humanity, maybe we should stop and consider the notion that Jon and Dany are actually the Hermione and Ron (or a pair of Neville Longbottoms, whichever you prefer) — two people who undoubtedly play major roles, but ultimately haven't been marked as the Night King's equal the way Bran has been.
The idea that Bran and the Night King are linked by both fate and magic would also explain most of the evidence for the Bran-as-Night King theory, but without all of the timey-wimey confusion. It's far simpler and with only seven episodes left, efficiency is going to be key in the storytelling moving forward.
So you heard it here, folks. Bran isn't the Night King. He's Harry Potter.
Game of Thrones finale airs Sunday at 9/8c on HBO.