Okay, it has been a while since I read these books, and neither I nor my better half (hubby) are familiar with this term. Could you please remind/enlighten us? Thanks.
Azor Ahai is a legendary figure in the faith of R’hllor. Thousands of years ago, he forged the sword Lightbringer which he used to defeat the darkness of the Great Other. This came at a price, however, as in order to unleash the sword’s true powers he had to plunge it into the heart of his loving wife, Nissa Nissa. A prophecy foretells that he will be reborn as The Prince That Was Promised.
Possible candidates:
Stannis
Jon Snow
Danaerys Targaryen
As Maester Aemon said - In Valyrian, there are not two words for the title, and so “Prince that was promised” may equally mean “Pincess that was promised”.
The light bringer with a magical sword to fight back the White Walkers.