David Benioff and D.B. Weiss explained in the Blu-ray commentary of The Dance of Dragons (2015) that Drogon was able to be injured by spears in that episode because he was an adolescent dragon and his impenetrable adult scales had not yet come in. As Drogon is now an adult dragon, his scales repel small projectiles, which is why arrows and spears have no effect on him, yet he is still vulnerable to large piercing weapons such as Qyburn's scorpion. This can be considered somewhat of a departure from the novels, where an adult dragon's scales are said to be virtually impervious to any kind of human weapon, and can only be penetrated by other dragons. There has been only one rare case of a projectile killing an adult dragon in the books, because it hit its one vulnerable spot: the eyes.
According to cinematographer Robert McLachlan this was the most expensive single episode of television ever made. Some media accounts identified the previous season's Battle of the Bastards (2016) the previous holder of this distinction.
The first time Sansa and Arya have had any direct interaction since A Golden Crown (2011), and the first time they have appeared together in a scene since both were present at the Great Sept of Baelor following the execution of their father, Ned, in Fire and Blood (2011).
In the obsidian mine, the symbols that Jon and Daenerys see among the cave paintings are symbolic patterns by which the White Walkers arrange the corpses of their victims: diamonds divided by a vertical line were seen once, in the first scene of Winter Is Coming (2011), and spirals of seven spokes spinning counter-clockwise after the battle of the Fist of the First Men in Walk of Punishment (2013). The latter was also seen in Bran's vision of the creation of the Night King in The Door (2016): a Weirwood tree surrounded by stone monoliths, arranged in a spiral pattern of seven spokes. Both symbols are now identified as magical runes of the Children of the Forest. In the novels, Arianne Martell and her companions Elia Sand and Daemon Sand find shelter in a cave, and discover ancient carvings of the Children on the walls; they are in the shape of faces, often with sad expressions.
This episode was Nikolaj Coster-Waldau's submission in the Supporting Actor in a Drama Series category in the 2018 Emmy Awards - his first nomination for the show. His co-star Peter Dinklage eventually won in this category.