The show sprawled after Season One, with at least two units—named the Dragon and the Wolf—shooting simultaneously. Weiss and Benioff leveraged their titles to take charge of the sets in exotic and temperate Spain, Croatia, and Morocco, leaving Cogman as their man on the ground in Belfast, where the show filmed the bulk of its interior scenes.

In Belfast, Cogman worked on behalf of Weiss and Benioff as fastidious keeper of the script, earning the nickname “Shakespeare” from Dance when he insisted that a line be read word for word. As a former actor, Cogman developed a reputation as an actor's writer. “He gets the life of an actor,” Coster-Waldau explains. “He's extremely respectful when it comes to not getting in your way.” Adds Turner, “Bryan's lines are always the ones that affect me the most.”

When it came time to divvy up who would actually write each episode, Weiss and Benioff preferred season premieres, finales, and the big, splashy set pieces in between.

Cogman, on the other hand, preferred the performance episodes, full of scenes, he says, of “people talking in rooms.” He wrote the two key moments of the Jaime and Brienne love story, from the Season Three bathtub scene in “Kissed by Fire” to the emotional Season Eight climax “A Knight of the Seven Kingdoms,” which sees the former Lannister antihero knighting the unlikely lady warrior. These quiet, shared moments stood out among all the dragon fire, shocking deaths, and big-budget battle spectacle.

“He has been a champion of my character Brienne and actually of me as an actor,” Christie says. “He had a real understanding of the trials the character had to overcome in order to achieve a sense of self-worth and how far we sometimes have to travel to move the narrative society has prescribed to us.”

“I can't imagine what it would have been like without Bryan,” Coster-Waldau says. “Thank God I don't have to.”

Illustration By Patrick Leger.

In Season Five Cogman volunteered to write what would become one of the show's most controversial episodes, in which the sadistic Ramsay Bolton rapes Sansa Stark, with Theon Greyjoy looking on in horror. Cogman, a father of three, had always taken a particular interest in protecting the show's younger performers on set. Turner compares him to a father figure, and Cogman felt he owed it to her to write the episode himself. “Why the hell did I choose ‘Unbowed, Unbent, Unbroken’?” Cogman asks years later, then responding, “Good question.”

The scene was lifted from another character's story in the books and incorporated into a larger gothic nightmare plot of Sansa's being held prisoner in her childhood home at Winterfell—a practical, and carefully considered, way to give Sansa, who isn't in the fifth book at all, a bigger role in the story. Weiss and Benioff suggested closing the bedroom door on Sansa, Ramsay, and Theon rather than showing the act itself. “I am the one, God help me,” Cogman says, “who said, ‘If we do this are we being dismissive of what that real horror would be behind that door? Are we being disrespectful of the severity of that situation?’ But we, of course, never wanted to make Sophie go through a graphic scene.”

The result was still graphic enough to spark immediate online backlash and heated think pieces; then senator Claire McCaskill publicly declared she would no longer watch the show. HBO issued no official response to the controversy, and Weiss and Benioff have never commented publicly, even deleting a question about it in e-mailed responses for a recent Rolling Stone story.

Cogman stands by the scene, though he acknowledges it served as a pivotal point in a larger cultural discussion about sexual assault on-screen, which had also been used as a plot device on Mad Men and Breaking Bad, among others. “I will never presume to tell someone how they should feel about the scene itself. And believe me, I really tried to listen to all the criticism surrounding it and will continue to listen,” Cogman says. “I do take issue with the presumption of bad faith on our part—the idea that we treated Sophie or the character or the subject matter callously. I think if you watch the scene and see how it fits into the character's larger narrative arc over the subsequent seasons, you'll see that's not the case. At least I hope so.”