For all the myriad revelations of Game of Thrones Season 6, book readers have taken small comfort in knowledge that the HBO series may not necessarily reflect George R.R. Martin’s unpublished books. The same can’t be said of Sunday’s big “The Door” twist, as showrunners David Benioff and Dan Weiss say the Hodor reveal came straight from the author himself.

You’re warned of full spoilers through Sunday’s latest Game of Thrones, as well potential scenes from The Winds of Winter, but those wondering how Bran’s time with the Three-Eyed Raven might come to an end got more than a few shocks by the climactic end of “The Door.” Not only did Bran seemingly learn the origin of the White Walkers and their Night’s King, but also that Bran himself was responsible for the childhood trauma that made “Wyllis” a simpleton only capable of saying “Hodor.”

It all went down as the Night’s King and his army invaded the Weirwood tree in which the Three-Eyed Raven attempted to upload the majority of his knowledge into Bran, as Meera desperately sought to wake the greenseeing Bran to help them. Bran successfully managed to warg into Hodor long enough for the present-day brute to hold back an army of Wights, though Meera’s screams of “hold the door” eventually took root in the younger Wyllis from Bran’s vision, who saw the time-traveler, and subsequently collapsed into seizure, repeating “hold the door” until it devolved into the “Hodor” of his namesake.

Obviously, that seems like a great deal of baggage for author George R.R. Martin to subsequently lay out in his books, but were there doubt, the post-airing “Inside the Episode” confirmed Martin as the twist’s engineer:

Benioff: We had this meeting with George Martin where we’re trying to get as much information as possible out of him, and probably the most shocking revelation he had for us was when he told us the origin of Hodor, or how that name came about. I just remember Dan and I looking at each other when he said that and just being like, ‘Holy shit.’ Weiss: It was just one of the saddest, and most affecting things. Even sitting in a hotel room having someone tell you this was going to happen in the abstract in some way and that ‘hold the door’ was the origin of the name Hodor … we just thought that was a really, really heart-breaking idea.

Granted, Weiss’ use of the word “abstract” offers some ambiguity as to the exact circumstance of Hodor’s origin in the books, it at least seems the “hold the door” phrase will explicitly come into play at some point in Martin’s work.

The episode itself had plenty more implications to bear on Season 6, and the series at large, but what should we make of Hodor’s tragic origin? What other Game of Thrones bombshells should we expect in the coming weeks?