On the NW = Lightbringer/Jon = TPTWP crackpot theory, here is our base to go off of:
1. Prophecy that Azor Ahai will be reborn as the Prince who was Promised:
"There will come a day after a long summer when the stars bleed and the cold breath of darkness falls heavy on the world. In this dread hour a warrior shall draw from the fire a burning sword. And that sword shall be Lightbringer, the Red Sword of Heroes, and he who clasps it shall be Azor Ahai come again, and the darkness shall flee before him."
2. Synopsis of Lightbringer Legend:
Darkness lay over the world and a hero, Azor Ahai, was chosen to fight against it. To fight the darkness, 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. He was not one to give up easily, so he started over. The second time he took fifty days and fifty nights to make the sword, even better than the first. To temper it this time, he captured a lion and drove the sword into its heart, but once more the steel shattered. The third time, with a heavy heart, for he knew beforehand what he must do to finish the blade, 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 breast, her soul combining with the steel of the sword, creating Lightbringer.
3. Oath of the Night's Watch:
"Night gathers, and now my watch begins. It shall not end until my death. I shall take no wife, hold no lands, father no children. I shall wear no crowns and win no glory. I shall live and die at my post. I am the sword in the darkness. I am the watcher on the walls. I am the fire that burns against the cold, the light that brings the dawn, the horn that wakes the sleepers, the shield that guards the realms of men. I pledge my life and honor to the Night's Watch, for this night and all nights to come."
Based on these three things we could have several options for how Jon = TPTWP and/or the NW = Lightbringer.
I think the simplest for Jon = TPTWP is the R+L = J theory, which also caveats with a lot of what Aemon mentioned about the Targaryens expecting some offspring to return them to glory or to their former powers.
As for The Night's Watch = Lightbringer, I think that we have correlations in their oath, and also in the 'forging' of Lightbringer with the blood of Nissa Nissa. In this case, Ygritte being killed by Jon is one option, or I would like to throw out there Jon himself could represent Nissa Nissa at the end of ADWD as the NW plunges their blades into him.
1. Prophecy that Azor Ahai will be reborn as the Prince who was Promised:
"There will come a day after a long summer when the stars bleed and the cold breath of darkness falls heavy on the world. In this dread hour a warrior shall draw from the fire a burning sword. And that sword shall be Lightbringer, the Red Sword of Heroes, and he who clasps it shall be Azor Ahai come again, and the darkness shall flee before him."
2. Synopsis of Lightbringer Legend:
Darkness lay over the world and a hero, Azor Ahai, was chosen to fight against it. To fight the darkness, 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. He was not one to give up easily, so he started over. The second time he took fifty days and fifty nights to make the sword, even better than the first. To temper it this time, he captured a lion and drove the sword into its heart, but once more the steel shattered. The third time, with a heavy heart, for he knew beforehand what he must do to finish the blade, 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 breast, her soul combining with the steel of the sword, creating Lightbringer.
3. Oath of the Night's Watch:
"Night gathers, and now my watch begins. It shall not end until my death. I shall take no wife, hold no lands, father no children. I shall wear no crowns and win no glory. I shall live and die at my post. I am the sword in the darkness. I am the watcher on the walls. I am the fire that burns against the cold, the light that brings the dawn, the horn that wakes the sleepers, the shield that guards the realms of men. I pledge my life and honor to the Night's Watch, for this night and all nights to come."
Based on these three things we could have several options for how Jon = TPTWP and/or the NW = Lightbringer.
I think the simplest for Jon = TPTWP is the R+L = J theory, which also caveats with a lot of what Aemon mentioned about the Targaryens expecting some offspring to return them to glory or to their former powers.
As for The Night's Watch = Lightbringer, I think that we have correlations in their oath, and also in the 'forging' of Lightbringer with the blood of Nissa Nissa. In this case, Ygritte being killed by Jon is one option, or I would like to throw out there Jon himself could represent Nissa Nissa at the end of ADWD as the NW plunges their blades into him.