This Pretty Much Proves That Bran Is The Three-Eyed Raven
John Bradley, actor of Game of Thrones' Sam Tarly, once told reporters that there is "no wasted line" on the HBO show.
Throughout the past 6 seasons, we have been privy to a few more-than-obvious clues that the Three-Eyed Raven is actually older Bran teaching himself, rather than the two being different people.
This theory cropped up back in Season 6 when it was revealed that Bran's actions could affect the past (cue tears for Hodor). The possibility of this sort of time loop, then, isn't at all impossible.
Game of Thrones Wiki
Back when Bran was still dreaming of Jojen Reed, he was told that the Three-Eyed Raven is him.
And, once the Little Lord's training was complete, the Three-Eyed Raven himself told Bran, "It is time for you to become me."
So it's been on everyone's mind for a while that the two may truly be the same person.
Episode 3 of Season 7, The Queen's Justice, all but proved the theory.
In the inevitable Stark reunion that came in last week's episode, Bran and Sansa's conversation was pretty telling.
Bran explains to his sister that the Three-Eyed Raven taught him to see everything that happens, anywhere in the world.
Understandably Sansa is confused; "I thought you were the Three-Eyed Raven," she says.
To which Bran responds, "It's complicated."
Um, yeah, duh.
Hypothetically, it wouldn't be very complicated to say something along the lines of "I was taught by the previous Three-Eyed Raven," or "Another Three-Eyed Raven passed this knowledge on to me."
If the real explanation is something so complicated that he can't bother to tell his sister, it must be something more than "Some old guy in a cave taught me things."