Out of all the characters in Game of Thrones, the one with the most mystery still surrounding him would arguably be the Night King. As most of the people in the series still know next to nothing about him (if they even believe he exists at all), fans are left to theorize his origins, as we do everything else in the beloved TV show. One fan on Reddit has a new idea on one major piece of history the Night King could’ve been responsible for: building the Wall.

User DanGliesac argues the Night King built the Wall after the battle against him during the Long Night. This time period, which took place thousands of years before the War of Conquest, saw the White Walkers coming to Westeros while a winter lasted an entire generation. This piece of history is told in GoT through stories passed down, without true confirmation of what really happened. The Redditor uses the phrase “History is written by the victors” to form their theory.

The idea is that since the Night King brings winter wherever he goes, as well as possesses great powers we don’t even know the extent of yet, he would’ve been the one most likely to be able to create the great ice wall. And his reasoning would’ve been simple: to keep out the Children of the Forest, the First Men, and anyone who could potentially be a threat. History books claim Bran the Builder was the one who built the Wall, but his people are the ones who wrote the stories. The theorist concludes:

“After this happened in an attempt to salvage the failure of not being able to kill the [Night King] I think the story was spread that the ‘good guys’ were the ones that put up the wall to stop the [Night King] from coming back when it was really the complete opposite.”

Commenters were quick to show their support for the theory on the platform, with one adding, “[The Night King] probably made a deal with Brandon the breaker: he makes the wall, Brandon and the Children write the spells so he can’t get back.”

This theory would make sense with the reveal Vladimir Furdik, who plays the Night King, told Entertainment Weekly last month, when he shared that his character is after one person in the final season. "People will see [the Night King] has a target he wants to kill, and you will find out who that is,” he shared. Going with the idea that he built the Wall for protection, it would explain why he’s now only trying to break through it, thousands of years later, because of someone in particular. Who that person is, however, is still up for speculation.

We can only hope that this time around, the Night King is not only defeated, but finally killed as well. It’ll all start coming together when Game of Thrones returns for its final season on April 14.

This article also appears on Mental Floss.