Her eyes are almost blinded when she looks at him, really looks, to see all his lives.
Life after life is pressed into his frame, a multitude of scarred men made hard and strong by the world. He is an inferno, a blaze of life and death and power that flickers.
He doesn't remember them all - with that many he can't; he'd go mad - but when she watches the man he is now, she sees flickers of them, fears that don't make sense for this youthful creature she loves.
His spirit is a strong one, steel that has been folded and pressed over and over, forged into a thirteen year old that stood against his father to save a battalion from a suicidal order - and it cost him dearly, but he stood back up, again, and again, and he walked out of that abusive house with his head high, his spine straight, and life gripped by the throat.
Katara doesn't know if she'll ever love someone like she loves him, with a deep well of respect and admiration, in this life or the next.
Zuko looks at her and is blinded, every time, by how beautiful she is. How lovely. She is kind to the depths of her soul, and he is attracted like a moth to this flame.
She has not lived as many lives as he - apparently she's more discerning in that regard - but he is drawn to the servant's heart, the warrior princess, the sugar queen, the woman who drives him speechless when he tries to compliment her, because how can he put into words how good she is?
He won't choose another life, not if he can't spend it with her, watching her, basking in her glow, seeing her grow into someone even more wonderful.
He'd climb an old temple of three thousand steps, carrying her the whole way, if it would mean he gets the next seven lives to see her smile.
"You've lived a lot of lives."
"Yeah, I was kind of a reckless kid a lot, always doing crazy stunts that got me killed. I'd immediately choose to come back, reincarnated again."
"And you never thought to slow down?"
"Guess I was in a hurry to meet you."