Daenerys’ fate was sealed long before the last dramatic betrayal. A major prophecy in the books spoke of a path to be taken, but it was never her path. It was for the Starks. Ultimatley nothing wa sabout her, when she believed it was. On top of that, she was always going to be betrayed for love and Jon Snow did it for more than his love for her. He did it for his love of honour, for his people and for his family. But just as the books opened with six direwolf cubs, so did Quaithe’s prophecy confirm they were at the center of everything. The endings for Jon, Arya, Bran and Sansa are contained in that prophecy.
in A Clash of Kings Daenerys is desperately trying to work out what she needs to do next.
The mysterious Asshai shadowbinder (the one with the striking metal and mesh masks over her face) Quaithe has been popping up in person and visions leaving cryptic clues.
Quaithe tells Daenerys: “To go north, you must journey south, to reach the west you must go east. To go forward you must go back and to touch the light you must pass beneath the shadow.”
Except this actually describes Sansa, Arya, Bran and Jon Snow.
Sansa has been discovering her destiny and her desire actually lies at Winterfell, not King’s Landing but she needed to learn through her travels and her destiny was always to be Queen of the North.
Arya went East across the sea to Braavos but her destiny and desire were always unflinchingly for revenge of those in the West who had wronged her and her family. And then far, far beyond. Arya will now go further West than anyone in history.
Bran has literally been travelling back and forward in time to fulfil his destiny, although his desires are no longer entirely his own as the Three-Eyed Raven. But his fate was always to be the guardian of mankind and now he will do it as King of the Six Kingdoms.
Jon Snow, aka Aegon Targaryen, has actually passed beneath the ultimate shadow (of death) and returned to the light of life. The image also connects to the idea he could be the one who was promised by the Lord of Light.
Ultimately the show fudged the whole Prince Who Was Promised but maybe Jon’s light is final understanding. He has always stuck to one unbroken devotion to honour and doing teh right thing.
That is why he killed Daenerys and that is why he can not be king. As Tyrion said, even good kings have wicked heirs.