AN: May be a two-parter, but the second part will be a while in coming.
From Darkness
The sun is brutal.
Zuko can feel it beating down on him like a flaming fist (a sensation he has experienced literally all too recently). Sunlight glares blindingly off the sea, and the kohl smeared under his eyes only helps a little. The air wavers above the deck. The iron surface is boiling hot even through the leather soles of his boots. Salt prickles on his skin, and he has to wrap his hands to keep the handles of his practice blades from slipping on his sweaty palms. The fabric chafes.
More irritating is the stiff feeling on the left side of his face and head, which feels like a skintight leather mask. The new skin around the edges of the browned area, where it was only blistered but not rendered completely dead, is still raw; it's been itching maddeningly and stings from the sweat and heat. Zuko keeps having to fight down the half-conscious urge to reach up and rip it off his face.
Sparring with swords is hard work, but somehow not nearly as hard in coming to him as firebending always was. Even with trying to get used to the diminished hearing and sight on his left side, even on this blazing kiln of a ship. The part of him that feels the scar most keenly whispers that it's no wonder his father is ashamed of him. A Fire Prince who can't bend fire to his will. Shameful, indeed.
He's allowing his thoughts to distract him, even though he knows better. His opponent thrusts and twists, wrenching the sword out of his right hand and sending it skittering across the deck. A moment later the second goes flying in the opposite direction.
"Again," Zuko barks, retrieving the weapons and resuming his stance. He lasted longer that time before being disarmed. He is improving.
"Prince Zuko, perhaps that is enough for today."
He turns to glare, the sharp movement shaking a droplet of sweat from his jaw. It hisses on the iron deck. The old man is sitting in the shade of the cabin with his pai sho board and a steaming teacup. Zuko takes only a breath to wonder irritably how anyone can bear to drink hot tea in these oppressive conditions before snapping, "I'm fine, Uncle. I need to train."
"But your opponent, I think, might like a break," Iroh suggests.
Zuko turns back to the crewman who has been teaching him to handle the dual Daos. The man isn't a firebender, and now that the prince is actually paying attention he can see that his shoulders and face are red not just from exertion, but from sunburn. His shirt is drenched with sweat and his stance halfhearted at best, chest still heaving from the last round. At the former general's suggestion he looks hopeful, straightening slightly, but he quells under Zuko's glower.
"Why don't you go have some dinner, Sergeant Joh," his uncle says. To Zuko's irritation, the man makes a cursory bow and scurries off before the prince can protest.
"Uncle!" Throwing the practice blades to the deck, Zuko stomps over and slams a hand down on the pai sho table, making the pieces jump. "We can't all be as lazy as you!" he snarls. "Some of us need to be in fighting shape!"
"You could also use a short rest," Iroh says placidly, sliding a few pieces that have been jostled back into place.
"I don't need rest! I need to be ready when we find the Avatar!"
The old man sighs, heaviness settling on his shoulders. "Well," he then says, as though he's just thought of something new and wonderful, "We could work on your firebending."
"No," Zuko blurts automatically, snatching his hand back like it's been scorched. Then, scrambling for his dignity, he draws himself up and crosses his arms over his chest. "I'm not done sparring. I'll just send for someone else."
"Prince Zuko, you must return to it eventually," his uncle says gravely, holding his gaze. Zuko looks away sharply. "You are a firebender. It is a part of you. You cannot avoid this. I know that your injury—"
"You don't know anything!" Zuko bites out, pivoting on his foot and striding back across the deck to retrieve his discarded weapons. He hasn't abandoned firebending. He's a prince of the Fire Nation. He doesn't give up on anything. He just—he just hasn't—had time lately.
For the last two months.
Spent mostly on a ship, waiting and waiting to sight land in various parts of the world.
Iroh is giving him a look he's learning to hate. Where his father would be angry for such backtalk, eyes searing and mouth set like iron and words biting like red steel, his uncle just regards him sadly. Understandingly. Sympathetically.
Pityingly.
"…It's too hot," he says lamely. Though after he's said it, Zuko himself is not sure whether he means it's too hot out here, with the scathing afternoon sun and oven-hot iron deck and eye-dazzling water, or if he means the scar.
Zuko would be willing to swear before Agni himself that the burn still feels hot, that there are still embers smouldering away beneath the dead, stiff surface. The healer claims it's no warmer than his undamaged skin and has very tentatively hinted that it might be all in his head, but it's his scar on his face and Zuko is pretty sure he knows how it feels a lot better than anyone else. Like that idiot knows anything. Uncle scraped him up off the street somewhere because he had no better prospects, like most of the rest of the crew.
Iroh simply sighs his heavy sigh again, returning to his game. "Very well then."
So Zuko practices the forms against imagined enemies, until the late afternoon sun lancing his blisters is more than he can stand.
When he finally does return to firebending, a full three months later, he meditates in the dark, away from the blazing ocean sun.