"What-" Zuko stopped, staring at the palace doors hanging ajar, and the lone helmet lying abandoned a few paces outside them. He broke into a run. Three scorched and unconscious royal guards lay just inside the doorway.

Zuko found another of their brethren fifteen paces further inside, half his face burned so badly it was practically gone. Zuko knew the man immediately despite the damage; it was Suikan. He was often assigned to Zuko's personal detail in the evenings. Zuko liked him. He knelt, leaning over Suikan, throat tightening painfully.

He was already dead. Probably it was best he was, in this condition. Zuko swallowed down bile, hearing a roaring in his ears as he rose to his feet.

Then suddenly, cutting through the dull roar of sound and overwhelming it, Zuko heard the crackling rip of lightning, and his blood ran cold.

Lightning meant-

Memories of his last Agni Kai rose up, choking him as he leapt over Suikan's body and ran down the corridor, following the sound deeper into the palace. Thankfully he found few more people along the way - a maid, crumpled and Zuko hoped only unconscious; another two guards who could be either dead or unconscious; a councillor Zuko hated and had wished he had the grounds to have imprisoned who was definitely dead. The man's left arm and shoulder were burnt so badly cracked and seared rib bones showing through his fine clothes and blackened flesh. There was no one else, and Zuko kept moving without checking on any of them, seeking the source of the lightning.

It wasn't much of a surprise to find the doors to the throne room scorched and askew. The huge metal insignia upon them had melted into ripples, a few trailing drips of gold streaking down over the wood.

Zuko barely took in those details before slipping through the doors, slowing only to twist sideways so he could slide between them without having to try forcing them any further open. A wordless shout made his stomach twist sickeningly again even before he took in the room - he knew that voice. Sokka was alive, and Zuko felt a rush of relief, but if he had heard lightning, Sokka was facing-

"Azula." Zuko said numbly, slowing to a stop a dozen paces into the throne room. Azula stood near the centre of the room, her back to him. The floor and several pillars around her were burnt and cracked, several more pillars had fallen across the floor in pieces, and the dais and throne were even worse.

His sister spun to face him with a twisted, too-wide grin on her face, jarringly contrasted by her eyes, narrowed and angry. "Zuzu!" she cried in a parody of delight. "So good of you to join us! Your little Water Tribe peasant pet and I were just wondering if you would make it in time to see." she taunted.

Zuko swallowed, pacing carefully in an arc around Azula, poised to deflect a blast from her and trying to look around the room for Sokka - for anyone else who might have been caught in here - at the same time.

"Zuko!" Sokka called out, breathless but at least well enough to speak. A slight movement drew Zuko's eyes to a swatch of dull blue half-hidden behind a cracked, collapsed pillar and the wreckage of the arch over the throne, just in front of the partially-crumbled dais. There he was. Zuko struggled to control the staggering feeling of his own relief at seeing Sokka whole, if battered and cornered.

And not exactly safe, with Azula here - how had she made it here? How had she escaped the hospital? Zuko thought with sinking horror of how many more could have died facing Azula there.

"Sokka, stay there." Zuko ordered, and Sokka made a scoffing noise and tucked himself up a little tighter behind the pillar.

"Aw, how sweet, worried for your pet, brother?" Azula asked, throwing a fire punch at him.

A slash of one hand through the air and Zuko tossed it away just as easily before he leapt, sending out a flare of fire with the solid landing of each boot as he hit the ground again. Azula laughed as she darted out of the way, lessening the impact with a spin and using her momentum to throw a growing wave of fire at him in turn.

Zuko growled and countered it with his own, halting it before the fringes of the wave could reach where Sokka was hiding. He kept moving in his semi-circle around Azula, keeping his distance but working his way around the room closer to Sokka, throwing testing blows and deflecting Azula's blasts in return as he went.

Her flame was as hot as it had ever been, vicious bursts of vivid blue roaring for Zuko as though it held every bit of Azula's single-minded fury. He had faced her at her worst before, though, and he had stood in the heart of dragon's fire and seen what flame should truly be, and Zuko had never been one to back down no matter the battle he faced. He struggled to keep her at bay without pressing on to the attack, searching for anyone else who may have pinned down in the throne room.

The doors near the back of the room were scorched and collapsed inwards, blocking any escape that way, but it seemed Sokka was the only one who had been trapped.

"I've come to take my rightful place, Zuzu; step aside!" Azula cried, lashing out with a twining pair of flame whips. "You have no right, no strength to hold our Nation!"

Zuko leapt back, pulling his legs up and twisting in mid-air to dodge as Azula flicked a third whip of fire up at his back. Sokka yelped and Zuko rolled sideways as he landed, already kicking out to throw up a flame wall, sending it racing across the space between Azula and Sokka and disrupting her next volley before it could reach him.

"You don't have a rightful place here!" Sokka shouted without coming out from behind the dubious shelter of the rubble.

"Our Father was to cede his throne to me!" Azula snapped, fire wreathing her hands as she took a step back, squaring her stance and throwing a column of flame at Sokka. "He was ascending and naming me heir!"

"We already fought this challenge," Zuko said, his heart racing as he brought his hands together to send his own fire wall roaring towards the ceiling, then sweeping forwards and down in a rolling wave towards Azula, "you lost! This is my place, and you couldn't keep it when you tried to take it from me!"

"And you can't even fight without your Water Tribe pets any more, Zuzu?" Azula said, grinning again as she swept away the looming wall with a quick sideways punch. "Hiding behind the girl then, and this one trying to protect you now?"

"You cheated and you still lost!" Zuko snarled, remembering that terrifying, hated day. He summoned up a ball of flame between his hands and began spinning long tendrils out from it, sending them lashing towards Azula. "Katara beat you then! Easily!" Zuko didn't quite know if it had been easy, but he'd wager on Katara to best his sister again, if it came to it.

Zuko thought of Mai and cringed, but while he might not be Azula . . . he had grown up in his father's palace too, he had learned how to strike where it hurt the deepest. He knew how the shock had hit Azula, and hurt her, losing Mai - and worse, losing her to him - and then Ty Lee. "And you may not know this, but friends protect each other!"

Azula howled in fury, the flames still blazing around them all roaring even higher. Zuko took a breath even as he backed up another pace, focusing hard and taking control of the fire near him, feeling it even as it faded from brilliant blue to vibrant orange. Azula hissed angrily and threw fire at his face.

Zuko lashed out with both hands as he huffed out a harsh breath and forced it back, his fire overwhelming Azula's and returning the volley. "I won't let you take the Fire Nation; I won't let you bring war back to the world!" he said fiercely, fists curling tighter as he took another step back, firming his stance and bringing flames together before him again, sending them towards Azula. This was his place and his duty, he was needed here.

"Then I will take it, brother!" Azula said, cutting through the attack with a leaping spin that brought down a broadly angled slash of her own flames. "And I will take our Nation back to the place it deserves! I will finish our Father and Grandfather's great work myself!" She drew herself up sharply and flames leapt higher around her.

Another barrage of fireballs thrown for him and Zuko stopped himself from dodging even as he retreated again, rubble crunching under his boots. He deflected some of the attacks and overtook the rest in a growing spiral of fire that built with every breath. That rain of fireballs hadn't only been aimed at him, but Sokka, too. The next was targeted even more directly, and Zuko retreated again, making himself a shield for Sokka entirely; he couldn't move far with Azula pinning them down like this.

"Zuko, careful." Sokka warned, too low for Azula to hear from across the crackling flames of their battle. He was close now, Zuko was backed nearly against the rubble of the dais and Sokka had scrambled a little deeper into the wreckage himself.

Zuko huffed. "What do you think I'm doing?" he snapped, deflecting another wave of flame, then throwing up one of his own, and a second behind it, sending them both at Azula. "Just stay down and let me protect you." he ordered Sokka, bracing himself. "I will not allow anyone to bring back the war our family began!" he yelled at Azula.

"You have grown too weak, Zuko!" Azula countered, shaking her head with a low frown.

The frown cleared a moment later under a laugh as she flung a flame whip at him. Zuko countered with another, crossing them and forcing her fire back before his own.

"You were always too weak," Azula bared her teeth at him, "and you have only grown weaker. You're no match for me, Zuzu!"

Zuko countered her next barrage quicker, but had to move to avoid a few stray tongues of flame as he struggled against the force and heat of Azula's fire. Though he wasn't weakening, not yet, he could feel the strain of this battle wearing on him - Azula likely could too, perhaps more than she once would have, with her lack of practise over the past years, but she was holding strong as well, and only growing angrier. Each new wave of flame risked getting further against his defences, the angry blue flames burning hotter.

"Azula! Back down!" Zuko yelled desperately, stepping back again but highly aware that he was running out of space in which to retreat. Sokka was tucked down as small as he could make himself already, sheltering behind Zuko's legs - he wasn't seriously injured, at least Zuko didn't think so, but he also hadn't risen completely to his feet since Zuko had reached the throne room, possibly couldn't - and he was getting closer to being singed with every attack from Azula, and every retreating step Zuko took.

He would have to stop and stand his ground, force Azula to move back and give him more space, and he wasn't sure his sister had enough sense in her head to go. Not now.

Another feckless shriek and a roar of flame from Azula, and Zuko twisted his stance and pushed forwards, letting out a harsh yell of his own. This time it was bright dragon flame with its beautiful twists of colour spilling from his hands. It struck the floor between them and roared immediately upwards, intercepting and devouring the vicious blue fire Azula had thrown.

"Azula, let it go!" Zuko argued, his heart aching as he pushed forwards again, a smooth deflection wrapping her flame into another burst of his own, consuming it, and sending it back.

She couldn't beat him, not any more.

It was a strange thought - Zuko had known for most of his life that Azula could best him, could probably even kill him if she tried - but . . . he was too strong for her now, and she was too weakened by her own fractured madness.

"No! I am the Fire Lord! I've always been stronger than you!" Azula yelled, her eyes blazing. "Back down, brother, this is my throne!"

"Azula, no-" Zuko shifted his stance as Azula's hands began to describe a wide, spiralling circle before her, a brighter, colder blue building around her outstretched fingers. His stomach twisted - he remembered the last time she had done this - but he had survived then and he would now, too.

"Zuko, don't let her hit you!" Sokka yelled from behind him, sounding faintly frantic.

Zuko frowned, briefly distracted. It wasn't like he had a choice - he couldn't block Azula's lightning with fire, couldn't block it at all, and if he tried to dodge, even if he could move quickly enough - possible, though not certain - he would leave Sokka exposed to it in his stead. Zuko's defence had already been limited by his need to shield Sokka, who could not defend himself from Azula's fire, nor even hope to flee from it when he couldn't so much at get to his feet.

Azula's lightning streaked towards them, and Zuko took a single step further to place himself squarely before Sokka once more. The lightning burned through him, cold and sharp, and Zuko clenched his jaw and let the bolt pour into him, guided it, then released it again. He caught his breath and steadied his stance again.

"That won't work, Azula!" Zuko shouted, throwing a curling whip of flame towards her feet, turning it loose from his hand with a final push, sending it twisting around her ankles and calves even as she retreated. It kept her moving, and in her shock even singed her a bit. Zuko's mouth twisted. He didn't want to hurt his sister.

He just didn't know if he had any other choice.

Zuko had the stamina to keep fighting Azula, after her time locked away in the hospital he was probably far more prepared for a long battle than she was, but even in her current state she was both smart and dangerous. The longer this fight drew on, the better the chances that either Zuko himself would get hurt or he would be unable to completely shield Sokka, or that Azula, paying what seemed to be no attention to their surroundings, would manage to do more significant damage to the palace around them.

And eventually someone else would come looking again . . . and Zuko might not be able to protect them from his sister as well.

Azula brought her hands up before her chest again, her face twisting with fury as she gathered another sparking rush of lightning, bigger this time, and threw it straight at him.

Zuko braced himself and caught it, feeling his body buzzing unpleasantly with the force and energy but forcing himself to stay calm and balanced, letting it follow the path he allowed through himself and free once more, narrowly avoiding Azula's head as he cast it back out. Azula shouted something else at him, but Zuko couldn't make out the words, panting and readying himself for her next move.

He hadn't forgotten how to handle lightning, but he couldn't keep doing this indefinitely. And Azula was building up more power this time, even as it gathered between her hands he could see the lightning fighting her now.

Zuko took a deep breath, loosening his muscles, and only let it drive him back a single step when the blast of lightning struck him. He let out a cry at the force of it, but it blazed through the same way he had guided each bolt of lightning he'd caught before. It was more powerful, but he could still control it, he just had to keep calm and focus.

Azula was gathering more lightning already. Zuko struggled not to hold on too hard, not to fight the push of the wild lightning inside him - he couldn't catch another while he held this one, but it had to be released again, and-

Zuko let the lightning go, back towards Azula and her next strike, hoping the powerful bolt would block Azula's next strike as she loosed it.

Azula shrieked, the lightning in her hands sparking and exploding as she tumbled backwards, off her feet. "Azula!" Zuko's eyes widened and he lunged forwards, every muscle feeling raw with the stress of the battle and his bones aching from the lightning.

Azula trembled once and didn't answer, didn't move.

Zuko kept his hands up and ready as he approached his sister, but she was still, save for the fading sparks of faint blue lightning around her. Her eyes were open and stared blankly at a far wall, her dishevelled hair splayed around her face. Zuko's fingers spasmed and he dropped gracelessly to one knee, reaching out and splaying his left hand over Azula's chest, just below her throat.

"Zuko?"

Azula was warm, but her chest was still - no flames, no breath, no beat of her heart beneath his hand. Zuko choked, faltering and nearly sliding from his knee to collapse on the floor. "Azula. . ."

"Zuko, are- Oof!" Zuko barely caught the sound of Sokka's voice, nor the thumps of something collapsing. A part of his mind filed them away, and wondered if Sokka was trapped - was he simply too injured to regain his feet, even without Azula threatening him? Was there a more worrying injury?

Zuko's fingers twitched and he reached up, brushing Azula's face lightly.

A scuffling sound, from much closer this time. "Zuko-"

"Azula's dead." Zuko said, his voice raw and cracking. "Sokka, my sister-" he couldn't go on.

"Oh- Oh. Zuko. . ." Sokka rested a hand on Zuko's shoulder and he flinched under it. Sokka didn't pull back, squeezing firmly instead, and then he bent and nearly collapsed on top of Zuko, startling them both. Zuko's head came up and he looked around, meeting Sokka's wide blue eyes. He swallowed painfully as tears pricked at his own, then looked back at his sister.

His sister's body.

"I killed her." Zuko choked out. "Sokka, I killed-"

"Zuko," Sokka said softly, and wrapped his arms around Zuko's shoulders, leaning against his back, blanketing him, "I- I'm sorry." he said, his voice a little cautious.

Zuko sobbed roughly, the sound shading into half a bitter laugh. No one was sorry for Azula - even Zuko couldn't- He hadn't intended, but she- What else could he have done? He had been. . .

Sokka squeezed him tighter, warm and comforting against Zuko's back. "I know this wasn't what you wanted, Zuko." he said, voice low, his chin almost resting on Zuko's shoulder.

"I tried-" Zuko's voice refused to come smoothly. "She wouldn't- I tried."

"Azula . . . didn't. . ." Sokka fell silent, pressing his face against Zuko's shoulder and gently rubbing one hand up and down where it was resting at the front of his left shoulder. "You were defending yourself. And- And protecting me."

"I had to." Zuko said, wincing, but unable to take his eyes off his sister's face.

"Of course you did. Azula," Sokka paused again as Zuko's breath hitched and he let out a pitiful sound, "didn't give you a choice."

Zuko had choices, but none he could have taken. He couldn't have just let Azula overwhelm him - he couldn't have let her go, he wasn't even sure he could have taken her down himself without-

And he couldn't have let her hurt Sokka.

"I had to protect you." Zuko said, and Sokka tensed.

"I'm sorry." Sokka said, voice thick. "I know that it- Having me here, and you couldn't fight her like you would normally-"

"No," Zuko said brokenly, shaking his head, "I couldn't- It's not that, I had to. . . I had to protect you. I would do anything to protect you. I care for you more than anyone-" he broke off. "I didn't think Azula would- She had another bolt ready to throw but it didn't come and when I redirected- when I let it- I didn't know." he sobbed, his chest aching.

Zuko had been fighting his sister but he hadn't intended to kill her, only to stop her.

He didn't even know if he could have stopped her without killing her, or if she would have bested him eventually - or if Sokka, or more guards, or servants, or someone else, would have taken the brunt of her fury instead. What else could he have done?

Sokka was murmuring in Zuko's ear, holding him tight around the waist, comfortingly close against his back as he tried to suppress the shaking working its way up from his fingers. They were still there when a squad of pale, fretful royal guards wrenched open one of the smaller sets of doors and crashed in.

Zuko was too numb to react by calling up flames, the alarm that flared in him weaker than it should have been. Fortunately there was no threat to them.

Zuko forced himself to breathe and raise his head and speak to his guards in as even and normal a voice as he could manage. He couldn't bring himself to pull away from Sokka's supportive hold, though, and he crumpled back into it a little more as two guards pulled Azula away and picked her up.

"Zuko. . ." Sokka breathed, one hand spreading out low over Zuko's ribs.

"I'm okay." Zuko rasped, and Sokka snorted. He couldn't really make himself speak any more convincingly, though, and he didn't truly believe it would help even if he could, not with Sokka.

Sokka patted him comfortingly and took over speaking with the guards - they knew him well, and knew he was one of Zuko's most trusted friends and advisors, so a nod from him was enough to have them listening to Sokka's instructions easily - as Zuko drew support from his arms. Azula's body was taken away to await Zuko's decision on what should be done with her, and the bodies of those she had killed taken away to be returned to their families, or in Suikan's case awarded the memorial with honour due to him as a royal guard killed in the line of duty.

Zuko shuddered at the thought, and Sokka squeezed him a little tighter.

"Sokka," Zuko realised belatedly, still feeling a bit slow and befuddled, "you were injured, Azula-" His voice cracked. "Are you all right?" He couldn't believe he'd forgotten enough to just let himself fall against Sokka so carelessly, without even checking to be sure he wasn't aggravating any injuries.

"Oh, I'm all right." Sokka said, chin tucking snugly against Zuko's shoulder. He shifted, with a low hiss of pain, and stretched out one leg. "I didn't dodge quite fast enough." His boot and trouser leg were burnt away, and the skin of his right calf and ankle beneath was red and blistered, swollen under the nasty burn. It was not nearly so bad as it could have been, however, to Zuko's distant relief.

Sokka lightly rubbed a hand over Zuko's ribs again and turned his attention back to the guards, giving a few more orders, taking care of the rest of the things that Zuko really should have been doing himself. When he tried to speak up again, though, Sokka only hushed him and one of his guards knelt, clasping his hand for a moment and assuring him they could handle what needed to be done. His eyes were sorrowful as he met Zuko's gaze, but sympathetic, not angry.

Zuko capitulated and let them. He would have to take charge again soon enough.

It wasn't public, and there was no announcement, but it was known among his people what Zuko had ordered done, in the end - only a few days after her escape from the hospital, and her attack upon the palace, Azula was burned with the honours due her as a princess. She had been a tyrant and a traitor and a deadly threat . . . but she had also been the Fire Nation's princess, and Zuko's sister.

The Fire Sages had assured him it wasn't necessary, as though that was what Zuko had been concerned with, and that she could still be burnt properly though labelled a traitor - or simply in a quiet ceremony, unacknowledged. Zuko need not even be there, one of them could oversee it as necessary. Zuko had refused flatly.

Sokka, his broken and burnt ankle splinted and wrapped in bandages, stood at his side overlooking the pyre, though really only the royal family should be where Zuko stood, even if this was the smallest memorial ever held for the burning of any member of the Fire Nation royal family. Sokka clasped his hand, and Zuko's breath caught. He lifted his chin.

Sokka squeezed hard, his free hand stroking Zuko's wrist. He took strength from the contact.

Zuko raised his hand and let fire rise up and spill from his palm with his breathing, coursing to his sister's pyre along with his silent farewells. His heart ached.

Azula was a traitor and had never held an official position other than that of princess, and there were no proper words to be said, really. So Zuko stood, watching, along with a lone Fire Sage, a few attendants, and Sokka standing at his side, holding his hand.

Zuko wasn't entirely sure he could have stayed as calm as he did without that steadying clasp.

They stood there until the pyre burned to embers, and then Zuko stepped forwards, Sokka staying by his side as he moved. He clenched his free hand into a fist. "Goodbye, Azula." he said thickly, able to offer nothing else, his fingers trembling in Sokka's hold. Then he allowed himself to be drawn away, Sokka's fingers trailing up and down his wrist again, as others came forward to deal with the remnants of the pyre.

A pair of royal guards were waiting for them outside the plaza, and another pair when they left the quiet mausoleum compound, falling in formation around Zuko and Sokka in silence. Zuko nodded a greeting to them but had nothing else in him, and Sokka stayed uncharacteristically silent, guiding Zuko back to the palace, and then through it to-

Zuko stalled as he realised he was at his own doors, but Sokka pushed insistently, and Zuko hadn't the will to resist. He was . . . tired, and worn, and he couldn't face anything or anyone else right now in any case.

He pulled away from Sokka and went inside, stripping out of his boots and surcoat, pulling the insignia from his hair and letting his topknot fall free. He realised he was crying and snarled at himself, angry and hurting.

"Zuko!" Sokka said, startled, and Zuko only belatedly realised that he hadn't left.

Zuko's breath caught and he shook his head, turning to the bed and falling onto it. Why was he crying? He scrubbed at his face and growled again, sniffing.

The mattress shifted and he looked up, surprised to see Sokka leaning in beside him. He swallowed roughly and swiped away more tears, expression twisting up, before shifting to fold in on himself.

"Zuko. . ." Sokka shifted on the bed beside Zuko, curling an arm around his shoulders. "It's . . . okay to grieve her."

Zuko's breath hitched. "She hated me." he said softly. "She was a traitor. She tried to kill me - Agni, she tried to kill you!"

"And . . . I won't mourn her death," Sokka said softly, "but Zuko . . . she was your sister. I don't know what she was like," he paused, "from what you've said maybe she was always a little . . . destined to be like she was, but no matter what else, she was your family, and it's not bad for you to grieve for her."

Zuko shuddered, turning onto his side, and Sokka tugged him a little closer, stroking his shoulder and back. "I killed her." he ground out, choking on the words. "I killed my sister."

Sokka didn't point out that Azula had wanted him dead for some time now, only stroked his face, blotting tears away with his sleeve. Zuko snorted wetly.

"Azula was a terrible person," Sokka said evenly, "and she needed to go down," Zuko remembered his uncle saying the same, years before, and his heart wrenched again, "but I am sorry that you were the one to have to do it. And Zuko . . . you were defending yourself - you were protecting me. And your people. And the world. You weren't trying to kill her."

"I could have stopped it. I didn't have to throw the lightning back at her, I could have-" Zuko's voice cracked and he couldn't go on.

"You could have delayed until the guards came," Sokka said, and Zuko cringed, curling his legs in towards his body, "and she could have killed them, or me, or even managed to hurt you badly, again." Zuko let out a rough little sob. "She might even have managed to kill you this time, she nearly did before. Zuko, I know you didn't want to kill her and I wish it hadn't been you . . . but Azula didn't give you much of a choice."

"Azula's specialty." Zuko said roughly. "Even if this time it didn't get her what she was aiming for . . . leaving you no choice but one was her. . ." he trailed off and Sokka stroked his hair, pulling him closer with a low huff of effort.

Zuko shifted to support his own weight and Sokka sighed. "Come here." he said, beckoning, and Zuko stilled. "Come on. You're heavy, and I can't move very well right now." He gestured at his right leg.

Zuko moved carefully closer, avoiding the splint and bandage, and Sokka pulled him abruptly down until Zuko was all but sprawled over his chest, leaning on his shoulder. His breath caught. Sokka curled around him, a little stiff but close and warm, and stroked his back.

"I might not be able to grieve along with you, Zuko," Sokka said softly, almost into his ear, "but I do understand, and I'm here for you. Let yourself mourn your sister, even if it's like this. She was your sister, and she's gone."

Zuko choked, shuddering, and Sokka hummed quietly, rocking him and curling around him a little tighter. He nudged Zuko's head until his face was tucked down against Sokka's shoulder, stroking his hair as he shook with sobs and soaked Sokka's shirt with tears.

"Zuko, I would do anything for you, too," Sokka said softly, and Zuko jerked with surprise, "and I know you're hurting, and I wish I could take that away from you."

Written for a Mousie's protective!Zuko request, including defending Sokka from Azula's lightning and something from a prompt list of Friendship to Romance Tropes on my Tumblr (Kalira9).