In order to play Arya as blind, actress Maisie Williams wore large 16 millimeter contacts that she could not see through for the stationary, dialogue-heavy scenes. For the fight scenes, she wore contacts with small pinprick holes in them, so she could see at least something, in order to not accidentally wound herself or others.
This episode confirms the popular fan theory that Melisandre is centuries old and her youthful appearance is a magical glamour. George R.R. Martin told the show runners this detail early in development for the series, and it was shared with Carice van Houten to inform her performance. Both the books and the series have implied that Melisandre is much older than she appears: in the fifth novel she thinks to herself that she has "practiced her art for years beyond count", and in the second season tells Stannis Baratheon she has been "fighting far longer than you" after his loss at Blackwater Bay. Melisandre's true form was implied by van Houten in 2012 shortly before the debut of the second season when she said, "I don't know how old she is, but she's way over 100 years", and by Oliver Ford Davies (Maester Cressen) who stated van Houten told him Melisandre was 400 years old. Melisandre appeared nude in her youthful form without her necklace in Mockingbird (2014), though van Houten confirmed this was an error in an interview with Elle, stating "That was an oops moment."
Melisandre's true aged appearance was achieved using prosthetics on Carice van Houten and superimposing her face onto the body of an older actress without other special make up. According to prosthetics supervisor Barrie Gower, the scene was originally planned for the fourth season but was pushed back twice: "When [the show runners] write the outline each year, for last two years, we got to this one point and we read this one gag and thought 'Oh my God, how the hell are we going to do that? ... And then it got pulled and we didn't do it in Season 4. And then, lo and behold, in Season 5 there it was again. And it's pulled again!"
Tyrion and Varys' scenes in Meereen were filmed in Castillo de Peniscola in Spain. In order to film these scenes, portions of the castle were sectioned off from the public and some guests staying in hotels overlooking these sections were relocated.
The scenes at Dorne were shot along with the rest of the season 5 Dorne scenes at Seville, so the crew wouldn't have to go back to that location for the scenes for this season.