The fever dreams were all so vivid...
“Stay with me,” Jaime pleaded. “Don’t leave me here alone.” But they were leaving. “Don’t leave me in the dark!” Something terrible lived down here. “Give me a sword, at least.”
“I gave you a sword,” Lord Tywin said.
It was at his feet. Jaime groped under the water until his hand closed upon the hilt. Nothing can hurt me so long as I have a sword. As he raised the sword a finger of pale flame flickered at the point and crept up along the edge, stopping a hand’s breath from the hilt. The fire took on the color of the steel itself so it burned with a silvery-blue light, and the gloom pulled back. Crouching, listening, Jaime moved in a circle, ready for anything that might come out of the darkness. The water flowed into his boots, ankle deep and bitterly cold. Beware the water, he told himself. There may be creatures living in it, hidden deeps...
From behind came a great splash. Jaime whirled toward the sound... but the faint light revealed only Brienne of Tarth, her hands bound in heavy chains. “I swore to keep you safe,” the wench said stubbornly. “I swore an oath.” Naked, she raised her hands to Jaime. “Ser. Please. If you would be so good.”
The steel links parted like silk. “A sword,” Brienne begged, and there it was, scabbard, belt, and all. She buckled it around her thick waist. The light was so dim that Jaime could scarcely see her, though they stood a scant few feet apart. In this light she could almost be a beauty, he thought. in this light she could almost be a knight. Brienne’s sword took flame as well, burning silvery blue. The darkness retreated a little more.
“The flames will burn so long as you live,” he heard Cersei call. “When they die, so must you.”
Here we see Jaime and Brienne with a pair of FLAMING swords. These two swords would make sense to be Widow's Wail and Oathkeeper. We already know that Brienne has the one and should Tommen die, the second would most likely pass onto Jaime. As they were both forged from Ice couldn't that mean that Ice was Lightbringer. Since the Long Night mostly affected the north it would also make sense for Azor Ahai to have been from the north and possibly even a stark.