Chapter Text
It starts with the small things: a kata he's struggled with suddenly gets manageable, he lands a jump that would've sent him sprawling on the deck before. His fire is more powerful, eager to answer his command when he calls for it.
His inner fire feels like the sun under his skin, thrumming in his veins along with his blood. He'd felt that way once, a long time ago - back when he felt his fire for the first time, before his relentless training made him contain it.
The mark stays under his skin, and Zuko is immensely relieved that no-one seems to notice it but him; he's prepared himself for an onslaught of questions the first time he was out of armor in Uncle's presence, but Uncle's eyes never stopped on his neck, continuing with their conversation as if there was nothing wrong with Zuko’s appearance.
Sometimes the mark throbs in odd intervals; it takes him an embarrassingly long time to notice the pattern.
He's standing next to Jee, discussing their next destination, when his hand brushes against the South pole on the map, and the mark starts to pulse rapidly, like a startled heartbeat. Zuko freezes, and the longer he stares at the South pole, the more excited the mark feels.
“Sir?” Jee sounds concerned at the sudden pause. Zuko shakes himself out of it before turning to his lieutenant.
“We've never checked the pole properly; set the course South.”
Doubt is clearly written all over Jee’s face, but for once he stays quiet.
****
The Fire Sages all stop to stare at him. While Zuko is used to stares, it takes him a few moments to realize their eyes are not on his scar, but on his neck. He scowls and fights down an ugly blush, noticing the identical marks on their necks, on the left side instead of his right.
“Not a word,” he growls, before the Avatar sends him flying down the stairs.
****
Zuko melts the ice with the last bit of power he had in reserve, gasping for air and stealing a few seconds to collect himself. To drown during the long night, when Agni will not be able to see him, is probably the worst death imaginable, and his hands shake slightly when he forces himself to get up. The mark throbs in time with his rapid heartbeat.
The moon blinks out, leaving him empty without Agni's redirected light. The light inside him burns with fury, which he unleashes on Zhao with all his might.
****
When Zuko crosses paths with the Avatar and his group in the Earth Kingdom, the water peasant - the non-bender one- has bright blue lips, the color too vivid to be of their world. Azula shows up before he can mention that.
****
During their exile, he lights a candle to Agni every evening. Uncle seems to approve of his sudden interest in religion, feeling generous enough to share some tales of his journey to the spirit world.
For once, Zuko listens.
****
Azula gives him a choice, and the mark stays silent, no matter how hard he's concentrating on it, praying that it throbs to give him guidance. It's his choice alone.
Naturally, he fucks up.
The sun doesn't feel so gentle on his back when he steps onto fire nation soil for the first time in three years.
****
The moment he truly decides to leave, the mark heat activates again, spreading warmth across his body, until it feels like he’s basking in sunlight on a summer day.
The day of the black sun comes, and he is his own sun, so when he goes to confront his father he is not afraid.
****
Zuko is blasted right off the edge, and for a moment his mind blanks out with animalistic terror when he begins his descent into the abyss below. The fact that vines are growing there for him to catch himself is nothing short of a miracle, and Zuko takes a moment to reflect on all the moments that Agni's grace has kept him alive. Another explosion goes off right above him, showering him with debris and somehow not severing the vine he's clinging to. Once he climbs back up he sends a quick prayer to Agni, the mark flashing briefly in response.
The Avatar accepts him, unenthusiastically, but he's still reeling after another too-close brush with death to really care.
****
“My first girlfriend turned into the moon,” Sokka says, and Zuko glances at the moon's pale face in the sky, trying to come up with a response to that.
“That's rough, buddy,” he offers awkwardly. They suffer a few more seconds of painful silence before he realizes: “Wait, is that why your lips are blue?”
Sokka winces.
“Yeah, spirit touched. At least most people don't see it, only Aang and the water tribe shaman have noticed so far.” He nods at the fire lily on Zuko’s neck. “Did Agni kiss you as well?”
Zuko opens his mouth when he realizes that Agni, in fact, had not kissed him at any point during the... encounter. He makes a noncommittal sound but Sokka notices his tell-tale blush and connects the dots almost instantly. Zuko knows he’s doomed when Sokka’s lips spread in a shit-eating grin.
“No way.”
It's going to be a long flight.
****
Inside the prison’s freezer, Zuko can't feel the sun in the sky. He’s hidden too far away from the surface; but he can still feel the one inside him, powering his breath of fire, so when Sokka comes to get him he is ready.
****
The sage gently puts the crown in his hair and then announces: “All Hail Fire Lord Zuko, Agni's true champion!”
The Fire Nation people present gasp and bow deeply while the other two nations cheer, not really understanding the gravity of the sage’s words. The sun shines down on them with almost physical force, like hands on Zuko’s shoulders, and Zuko knows he can do this.