Giant theorists think more hints at this potential twist have dropped through the years. One of the biggest is in "Sigils," a teaser trailer for season 7, which closes with a giant shot of -- wait for it -- a blue eye.
Then again, maybe the eye was just a foreshadowing of the Night King's arrival in the Season 7 finale.
Called the "biggest" fan theory about "Game of Thrones," this one holds that our resurrected hero is "The Prince That Was Promised," aka Azor Ahai, a legendary, fire-sword-wielding savior figure from the books whose name has not yet been uttered on the series.
This theory is nearly as accepted as the Jon-is-Azor theory. There's even a Redditor who has made a color-coded chart that shows the princess as the odds-on-favorite. It shows her hitting all the right Azor notes, including a shared talent for bringing stone dragons to life.
The reformed smuggler is viewed as something of a dark-horse candidate. But an elaborate theory makes a case that the series has hinted at the so-called Onion Knight's destiny going back to when Davos retrieved a cooled, but once-flaming sword from the sand. The theory goes on to give Davos credit for bringing Jon Snow back to life, an act that could be described as having awakened a dragon from stone.
This "crazy" theory posits that a High Valyrian translation error has led us to believe Azor Ahai is the Lord of Light when he's actually more like the Lord of Gold. Jaime is, of course, the most golden "Game of Thrones" character, given that he literally has a golden hand.
Confirmed: Tyrion Lannister betrays the Lannisters
This theory -- borne out in Season 7, Episode 3 -- featured Daenerys' army attacking the Lannisters' Casterly Rock. The attack was planned with insider knowledge provided by one of the royal family's own: Tyrion.
Quashed: Bran Stark will lead the Night King through the Wall
Fans thought the the young warg would unwittingly bring the leader of the White Walkers -- and his army -- into the Seven Kingdoms. Bran's arm, marked by the Night King in season 6, would act as a GPS device and show them the way inside.
Now we know the real way that the Night King breached the wall, and it wasn't via Bran.
In the "Game of Thrones" universe, there's already been a Mad King.
The Cersei theory supposes that, now that Jaime's beloved sits atop the Iron Throne, she'll go down the same path and order the fiery destruction of King's Landing. After all, she's already blown up half the city.
We now know once and for all who begat Jon Snow: The secretly married Lyanna Stark and Rhaegar Targaryen. According to a pair of theories, Jon, who assumed the title "the King in the North," will soon know the truth, too. After all, Samwell and Bran already do.
Now that Jon has been confirmed to be a blood member of the dragon-friendly Targaryen clan, he's all but considered a lock to join his Aunt (yes, aunt) Daenerys heading into battle on one of her two remaining beasts.
The ice dragon theory also posits that the zombie will, oddly enough, fight for Jon Snow and the North. The King of the North, who was also resurrected, will be able to tame the ice dragon and ride it.
The Wall at Eastwatch is already breached. But this theory suggests that the Horn of Winter -- found by Samwell Tarly -- will awaken an ice dragon in the Wall as well, perhaps causing another part of the structure to collapse.
Earlier in season 7, Euron Greyjoy promised Cersei a gift in exchange for an allegiance. Could that gift be something he's already delivered, such as Yara or Ellaria? Or could it still be the Dragonbinder, a horn that can supposedly control a dragon?
Bran the Builder -- also known as the first Brandon Stark -- built the Wall and Winterfell centuries ago. This theory suggests that the second Bran wargs into the past to construct the Wall... and tells people his name while he's there.
With Bran's powers to warg into the past, could he have caused the Mad King to actually go crazy? The belief is that during his viewing of the past, Bran will call out to Aerys Targaryen, causing him to hear voices.
Remember Gendry? He's the illegitimate son of Robert Baratheon, who was shipped off on a boat earlier in the series. The rumor that Gendry would make a triumphant return to team with Jon Snow and Co. also came true in Season 7.
This is a less popular theory, but it's a good one. Like the Jaime-kills-Cersei supposition, it's rooted in a scene from the books wherein the witch Maggy tells a teenaged Cersei she will be choked to death by "the Valonqar." The latter is said to be High Valyrian for "little sibling."
The Jon-kills-Cersei theory holds that anyone who is a little sibling could be the culprit, including one Jon Snow.
Perhaps the only thing less surprising to "Game of Thrones" fans than Jaime Lannister taking the life of his sister would be Tyrion Lannister, another of the queen's brothers, doing the deed. Like Jaime, Tyrion pretty much fits the Maggy prophecy to a T.
Arya Stark is dead... and has been dead for a while
In season 6, Arya kills the Waif in a darkened alley... or does she? The Arya-is-dead theory holds that it was actually the Waif who prevailed, and then assumed Arya's identity by wearing her face. This turn of events is hinted at, believers speculate, when Jaqen H'ghar tells Arya (or should we say, the Waif?) that she has "become no one."