I have a question regarding the Night King:
I haven't read the books but in the TV series it has been indicated that the dead dudes attack every 1000 years or so , that is why the built the wall. Does the NK get killed every time and somehow gets resurrected (kind of like the Borg Queen)?
Also after the dragon fire failed to kill him, it seemed like the NK smiled, which was creepy.
Well, there was the Night’s King of ancient legend, who lived during the Age of Heroes, that did some pretty horrific things, including “making sacrifices to the Others” (basically, the White Walkers). It’s possible the show writers latched onto that legend and retooled it for the show. But, yes, there was no direct analogue in the books. Then again, there are still two more books planned that nobody’s read yet (if ever). Perhaps there is a driving force behind the approach of winter that we haven’t seen yet.There is no Night King in the books. He was invented for the show. It's possible he could be introduced in the 6th or 7th books though, but that doesn't seem likely.