Audiences have speculated on the origins of the Night King in Game of Thrones, with some wondering if he’s a Targaryen. It’s not entirely uncommon in George R.R. Martin’s A Song of Ice & Fire book universe for such character reveals to take place. After all, between the books and the show, there are already multiple characters in the North who were discovered to be of Targaryen origins. Jon Snow is Rhaegar Targaryen’s son in the show, Maester Aemon of the Night’s Watch is a Targaryen, and the Three-Eyed Raven is suggested to be a Targaryen bastard in the books.
Given how mysterious the White Walkers are, it’s not too big a stretch of the imagination to theorize about their potential origins. However, Game of Thrones showed a scene in which the Night King was created, and there’s enough information there to answer at least some questions about his life and motivations. Bran Stark’s visions unfortunately never painted the full picture of the White Walkers audiences hoped for in the Game of Thrones ending, but they at least confirm the Night King isn’t a Targaryen.