Arya's death list was significantly longer in earlier seasons than the version she recites in this episode (Meryn Trant, Cersei, Walder Frey, and Gregor Clegane). The previous versions included Melisandre, Beric Dondarrion, and Thoros, who are all still alive. She had put them on the list in season 3 because they took Gendry away, but she has since focused on worse enemies. While Walder Frey is included in the show, he never appeared in Arya's list in the books, as she is unaware of which Freys were responsible for the Red Wedding. Ilyn Payne, who carried out her father's execution, was omitted by the show runners after Wilko Johnson, who portrays Payne, retired from acting after being diagnosed with pancreatic cancer (from which he later recovered).
The episode title is a reference to a temple in Braavos, dedicated to the Many-Faced God. It also serves as the headquarters of the guild of assassins known as the Faceless Men.
It is the first time that the name of the disease that disfigured Shireen's face is spoken: Greyscale. It is somewhat analogous to the real-life disease of leprosy, although leprosy is not a fatal disease in itself.
The House of Black and White is seen as a universal temple, as the Many-Faced God is 'death' and nearly all religions have a God of death in the series.
Lollys tells her future husband Bronn that she doesn't want the flute playing at their wedding. Perhaps this refers to what the show-runners David Benioff and D.B. Weiss (who also wrote the episode) told Ramin Djawadi when they hired him to compose the score for the show: they insisted that no flutes should be used, as they consider it a fantasy cliché.