hmm... you guess there is just only one Night King ... I say there were two ;-)... because Lightbringer needs three Battles to be created ... and we are shown the final Try ;-) There must be 2 ... and there were 3 swords racing to become it ... Oathkeeper , the sword of the morning , and the red sword of heroes .... and the winner will be Lightbringer ;-)... it´s the dance of the dragon ...don´t forget ...there were just 2 gods
The nights king was not, a commander of the nights watch. There different people. The nights king who was lord commander was killed by an alliance of the Stark's, and the king beyond the wall. The show is obviously saying there is and has only been one "nights king". So it don't matter which one your talking about.
I'm pretty sure Jon and Dany will die. I also think there is a good possibility that all the dragons will die and maybe magic dies. Heck, I'm not 100%.
How it will end? I think, Jon will become an undead, not able to die any more. And he has to sacrifice Dany, forge Lightbringer and kill the NK to end the Long night. After that he might want to lay down his title, but he will be the only accepted king, ruler in Westeros and he will stay and rule as an undead, eternal king, kind of a Jesus Christ forever - good for the Realm, bad for himself: lonely forever, his only, last chance for love died with Danaerys (killed by himself), only duty to be the shield that guards the Realms of Men. I think, Dany's fate is very much foreshadowed in Ygritte's story: the fiery woman, big love... but for Jon his duty to protect his people will be ore important than love or happiness.
