Isaac: It was a really challenging thing to do this season. I had a meeting with David [Benioff] and Dan [Weiss], our showrunners, before we started filming. We had a chat about how we wanted to play Bran this season, and they suggested Doctor Manhattan from the Watchmen comic. Bran was slightly based on that, existing in all these different times at once, knowing all these various things, being this emotionless rock connecting these different timelines and the history of the universe. We wanted that, but we didn't want a boring, monotonous character who would just go, "Yeah, I'm the Three-Eyed Raven, blah blah blah." It becomes a bit unbelievable, and also it becomes a bit dull. Not that the whole thing isn't completely unbelievable, but you know what I mean.
We also wanted to make sure that there was a bit of Bran left, a glimmer of a person still in there. It's like he's the first cyborg. We just connected a supercomputer to a human being's brain. He's a mainframe, but there's a little bit of his personality. More often than not, though, Bran is a vessel for human knowledge.