Azor Ahai was originally a man that labored for one hundred and eighty total nights before creating his perfect sword. In order to allow the sword to become the Lightbringer he thrusts the blade into his wife’s breast; her soul becomes embedded in the sword. This Lightbringer is the only weapon that can rival the darkness that has fallen over the Seven Kingdoms. This darkness that is referred to is the winter that everyone seems to be fearful of during Game of Thrones.
Melisandre, who is deemed the Priestess of Light, recites a prophecy that King Stannis Baratheon is Azor Ahai Reborn. This is extremely important because Azor Ahai’s return is prophecied to save the world from darkness. Even though Melisandre believes that Stannis is Azor Ahai, and Daenerys is later proclaimed Azor Ahai by another prophet, many believe that Jon Snow is the true Azor Ahai. This is supported by the fact that Melisandre’s predictions have been wrong before. She also later admits that she has seen Stannis fighting alongside Jon Snow.
Jon Snow is also hinted to be Azor Ahai throughout the franchise. For one, when Bowen Marsh’s salty tears fall upon Jon Snow’s wound smoke erupts, like in the tales of the Azor Ahai. Also, Melisandre constantly asks R’hilor to show her Azor Ahai, but she is only shown Jon Snow. If this is not a giant hint, then I do not know what is. Jon Snow also has a dream that he is in armor enveloped in ice, although his blade is not frozen over. His blade is red and is on fire, much like the Lightbringer.
So while Melisandre is set on Stannis being Azor Ahai and Daenerys is proclaimed the Azor Ahai, Jon Snow is also a strong candidate for the title. He is almost directly pointed out when Melisandre points to her visions having both Stannis and Jon Snow in them, as well as when R’hilor shows Melisandre only Jon Snow.
This speculation of who is the reborn Azor Ahai is very important, because if that person falls, then the rest of the world will fall with them. Therefore, whoever turns out to be the reborn Azor Ahai will hopefully lead the world of Game of Thrones to a more prosperous and less war torn world. This man or woman will banish the darkness, hopefully, which begs the question: will the reborn Azor Ahai claim the throne as well? Only time will tell.