Game Of Thrones: Why THAT Death Was A Mistake (& How It'll Be Different In The Books)
3. Will Arya Be The Saviour?

It's long been expected that Jon or Daenerys would ultimately be the one(s) to save the world from darkness, whether as Azor Ahai or not. Jon, in particular, has had a lot of narrative setup with regards to facing the Night King, but the showrunners decided to pull a fast one by having Arya Stark kill him instead.
It fits well within her arc on the show, in a sense, given how much we've seen her training to fight and how much of that in turn has revolved around death, even if the bigger theme has been vengeance as opposed to stopping the dead. Still, it's an awesome moment for one of the show's best characters, but will it happen in the books?
Read More: Game Of Thrones Season 8 - 'The Long Night': Every Death Ranked
As established, it can't be completely replicated in the text, because the Night King doesn't exist. There isn't just one single enemy to defeat, which means Arya cannot have this ultimate heroic moment. But she can help fight against the army of the dead, and probably will. She is training to be a deadly assassin after all, and that will come in very handy when she returns home and reclaims her identity, much like it does on the show (albeit with some differences in terms of who is involved in that story, with, say, Lady Stoneheart perhaps taking on something resembling the Beric role here).
Since there isn't a Night King, Arya can't have the hero's moment. But she can have one heroic moment among many. There are a number of Others to be defeated, and that allows for various main characters to each play a part in killing them. There'll be lots of deaths and sacrifices within that, helping to underscore the futility of war that is important to Martin's story, and means it comes down more of a collective human effort than it does one person killing one villain.