I. Eyes
The first time Zuko noticed Katara's eyes was when he first attacked the Southern Water Tribe. As he grabbed ahold of her grandmother and yanked her away, he looked up fiercely to see her confused and terrified granddaughter staring at him apprehensively. For one breathless moment their eyes met, and he was staring into those ocean blue eyes, and he saw the fear on the surface and the courage and defiance that lay beneath. Then he tore away, still trying desperately to forget the feeling of a racing heart and butterflies in his stomach.
II. Name
The first time he heard her name was much, much later, in a small Earth Kingdom port, when he heard her brother screech, "Katara!" From then on, he would whisper her name in his sleep – Ka-tar-a, Ka-tar-a, and even during his waking hours, he would repeat it over and over, almost like a mantra: Katara, Katara, Katara, Katara, only stopping when Iroh would ask why he was muttering so. Eventually, Zuko began to realize how ridiculous this was, and began to train himself to forget that a girl named Katara ever existed.
III. Laugh
He first heard her laugh while stalking in the woods and crouching in the bushes near their camp. At first, a spark of jealousy ignited within him when he realized that the avatar had made her laugh ( a small voice inside asked, Why wasn't that you?), but it vanished as quickly as it had come. However, the sound of her laugh seemed to fill his every sense, echoing in his head like some sort of undead phantom. Needless to say, Zuko did not attack their camp that night.
VI. Kiss
She would have found him shallow for it, but there was something in that soft, electrifying kiss that made him feel like never before. It was almost as if she was completing him, reawakening something deep inside that seemed to prove his deepest nature was that of his mother's. Of course, it might have helped that she was such a good kisser, as well.
V. Heartbeat
He gentle pulsing of her rhythmic heartbeat as she rested her head on his shoulder seemed to match the beat of the ocean, the forest, everything. But the best times were when her heartbeat blended with his own, so that they seemed to be swaying, rocking back and forth like a giant pendulum. At these times, it seemed if they were not one, but two; not just Zuko and Katara for as long as the moment lasts, but Zuko and Katara, now and forever.
Was that OOC? 'Cause I'm worried it was either out of character for Zuko, or way too short.