Azor Ahai was a legendary hero who was said to have lived in Westeros approximately eight thousands of years before Aegon's Landing. He fought and defeated the Others in the War for the Dawn during the Long Night. Wielding a sword named Lightbringer, which was said to carry the soul of Nissa Nissa, Azor Ahai's wife, after he drove the blade through her living heart to temper the steel.
To fight the darkness that lay in the world, Azor Ahai needed to forge a hero's sword. He labored for thirty days and thirty nights until it was done. However, when he went to temper it in water, the sword broke. But he was not one to give up easily, so he started over.
It took him fifty days and fifty nights to forge the sword the second time, even better than the first. To temper it this time, he drove the sword into a lion's heart, but once more the steel shattered.
The third time, he worked for a hundred days and nights until it was finished. This time, he called for his wife, Nissa Nissa, and asked her to bare her breast. He drove his sword into her living heart, her soul combining with the steel of the sword, creating Lightbringer, the Red Sword of Heroes.
According to prophecy, in ancient books of Asshai from over five thousand years ago, Azor Ahai is to be reborn again to challenge the Others. This will occur after a long summer when an evil, cold darkness descends upon the world. It is said that wielding Lightbringer once again, Azor Ahai will stand against the Others and if he fails, the world fails with him.