[spoilers extended] How do you think the conflict against white walkers will look like.

Assuming there is no NK in the books, and white walkers dont just follow his orders and plans. How will the future confict against them in the books look like. Are they just a part of the Long Night and come with it. Or is there maybe more nefarious intent behind them. Like a confict between the Great Other and Lord of light. Do you think we will see a NK like character in the books? Or was it created only for the entertainment purposes of the TV show.

Also the prophecy of Azor Ahai creating the lightbringer and ending the long night. Did he litterally create a sword to kill something specific? was the sword a metaphore for something different that could counter the Long Night. I know that it´s most definitely not true, but what if Azor Ahai created the Lord of light, as the means/sword against darkness/cold.