With the chaotic climax of the Battle for Winterfell and the destruction of the Great Sept of Baelor, it’s easy to forget the biggest revelation in Game of Thrones season 6: That Bran Stark has become the last greenseer and can use his powers. Shocking developments in King’s Landing and non-shocking ones at the Tower of Joy nothwithstanding, the greatest moment in the season still has to be Hodor’s horrifying death. “Hold the door” is the key secret of the season. But it also tells us not to expect big changes from Bran… because those changes have already happened.

Bran Has Already Used His Powers From The Future

So here’s how Bran’s power works, as best as we can tell: He can change the past directly. But by changing the past, he can only create the future—the present—that he already exists in. To him, in that moment, everyone was screaming at Hodor to hold the door. And in the past, Bran accidentally changed Hodor from a normal boy into “Hodor,” the gentle giant who was capable of holding the door. The present didn’t appear to change; Hodor had been Hodor all along, but until that moment, Bran had not yet made that past come to be. Simpler version: The effects of Bran’s changes in the past are already being felt in the present.

That means that Bran can’t change the present we see in the show. He can’t make himself not fall out of that tower; he can’t save Robb Stark’s life in the Red Wedding. Those things already happened. Or, rather, he possibly could change those things, but does not. If he did, they would never have happened. What he can do is make the Mad King mad, or ensure that Benjen Stark survived to become Coldhands, to make Melisandre follow Stannis or even make sure that he himself did fall out of that tower. Of course, his power is still at least somewhat subtle, and not entirely under his control. He can’t change whatever he wants.

Everything that Bran will someday change in the past has already been changed. He chose the present that we see in the show. The excitement in the future will be seeing the decisions he made—whatBran did choose to change and why. If he made the Mad King mad, why? Was it to warn him about the Others? To ensure that Robert would rebel and the prophecy of the prince that was promised would come to pass? Or was it simply by accident?

Bran isn’t easy to digest. His power is essentially to create a closed time loop that has already been fulfilled, and those are always confusing. But it’s a powerful power nonetheless. After all, he can change the past. And he has, and we’ve seen the world that resulted. He must have made some interesting choices along the way.