WARNING: The following article contains spoilers for the Season 7 finale of Game of Thrones, which aired Sunday on HBO.
The seventh season of HBO's Game of Thrones concluded Sunday with one of the most cataclysmic moments of the series to date, and according to the series' showrunners D.B. Weiss and David Benioff, the fall of Westeros' (formerly) indestructible Wall had been in the works for quite some time.
"Many years now, we've known this would be the ending of the penultimate season," Benioff revealed in HBO's Inside the Episode special. "The Wall's kept these things out for 8,000 years," Weiss added. "There's no reason that it can't keep doing that, unless something puts a hole in the Wall."
Now fans know exactly what that "something" was: Daenerys' fallen dragon Viserion. While attempting to evacuate as many men off of the Wall as possible, Beric Dondarrion and Tormund watched helplessly as the undead dragon, now under the control of the Night King, unleashed ice breath across Westeros' last line of defense.
"There's one thing on the board from the beginning that is now big enough to do that, and that's a dragon," Weiss continued. "It just started to suggest itself as a logical way forward ... We needed it to be a thing you go out of the season on."
With nothing now separating the people of Westeros from the army of the undead, it will take the combined efforts of just about everyone to have a chance at survival during the series' six-episode final season. But, of course, it wouldn't be Game of Thrones if everyone played along, as Cersei looks to continue her streak as the queen of ulterior motives.
"The first four or five years of the show, it was the expanding universe, and as we get near the end of the show, the universe contracts," Benioff concluded. "The characters are going to a place that they never have before ... where they're facing the conflicts that will decide their fates."
Game of Thrones' final season does not yet have a release date, but the penultimate season is now available in full on HBO Go and HBO Now. Based on George R.R. Martin’s bestselling fantasy series A Song of Ice and Fire, the hit drama stars Peter Dinklage as Tyrion Lannister, Nikolaj Coster-Waldau as Jaime Lannister, Lena Headey as Cersei Lannister, Emilia Clarke as Daenerys Targaryen and Kit Harington as Jon Snow.