Game of Thrones' latest episode airs its first spoiler for book readers

Last night's episode of Game of Thrones — which Polygon's Ben Kuchera calls one of the most heartbreaking — marks the first time since the series began that spoilers for book readers were aired.

[Warning: This post contains spoilers for the most recent episode of Game of Thrones.]

In the episode, called "The Door," fans were finally given some insight into how Hodor, Bran's most trusted ally and right-hand man, got his name. By revisiting the past, Bran causes Hodor, whose name was originally Wyllis, to suffer a mental breakdown. It's what led to Hodor being left forever in a childish state, only able to utter the one word that would eventually become his name.

While much of this season has been full of guesses over what will appear in author George R.R. Martin's new book and what won't, showrunners David Benioff and D.B. Weiss confirmed the Hodor arc most certainly will.

"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," Benioff said during a post-airing special of Inside the Episode. "I just remember Dan and I looking at each other when he said that and just being like, ‘holy shit.'"

Weiss echoed Benioff's sentiments, adding that sitting in a hotel room and hearing the origin story over the phone was one of the saddest moments for the two of them.

"We thought it was a really, really heartbreaking idea," Weiss said.

Although this is the first time the events of the show have explicitly detailed what's about to happen in the books, it shouldn't come as too big of a surprise. Both showrunners and Martin said that this season would inevitably ruin surprises in the series' next book. Martin even took to his LiveJournal page to apologize to fans for not being able to finish the book in time for the new season.

Game of Thrones airs Sunday nights at 9 p.m. ET on HBO.

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