A/N. Sorry for having been absent for a few days, had a rather horrible presentation for work today on which I had to work the past days. But I'm back!

"Explain, once more, because I'm not that bright, why in the name of Tui and La you have to fight her alone?" Katara asked, her voice cold as ice. There were standing near the entrance of the plaza, as the Fire Sage had interrupted them to make the few prayers needed for an Agni Kai. Azula had just smiled and stepped away, as they had done.

"An Agni Kai is archaic! They are only done in the case of severe insult. I… I have done them before." Zuko whispered urgently, "and, with a bit of luck, the comet is gone by the time we finish the fight. No one can intervene in an Agni Kai. The soldiers, the Fire Sages… They all have to watch. And that means there is no risk anyone else gets hurt!"

The waterbender still didn't like it. She was being robbed of her own role in the fighting, by Zuko being an outdated conservative fool. They needed to fight Azula, kill her and claim the Fire Nation throne before the comet disappeared. If they didn't, and Aang lost… Then Ozai would still be Fire Lord. And then, they would be in trouble.

"You have done Agni Kai's before? Who insulted you?" Katara groaned. Of course the idiot had done them. It seemed a very Zuko like thing to do. At least, the Zuko from before he betrayed his family and joined them.

"Actually, I was the one who insulted someone." He spoke thinly, pointing to his scar. Katara, who had wanted to laugh, stopped as soon as he gestured towards the raw skin.

"Ozai." She didn't need to ask. Zuko's hatred for his father went much deeper than just disgust at the treatment his nation, as he had claimed at the beginning, in the temple. No… This was much more personal.

The firebender looked at her for a few seconds, before nodding curtly. So Aang had been right with the idea that it had been Ozai… Spirits, what kind of father would do that to his own child, to his own flesh and blood? She hoped that Aang would at least make the Fire Lord pay for his actions.

"Still, I don't see why we should adhere to the rules! Azula is clearly not going to!" She hissed, putting the conversation about Ozai on hold, "Tell me the rules."

"Agni Kai's are sacred, and highly regarded as the judgement of Agni himself! If one disgraces himself during one, they are rejected by any follower of Agni. Why do you think I was banished? You can only be restored by doing something so highly honourable that it washes away the shame. And the rules are simple! Only firebending, and no one may help. Katara, you may, under no circumstances, help. Do you understand?" Zuko spoke, and the tone clearly was meant to have to objection to it.

"And under what circumstances can I actually impale your sister?" She asked, feeling the water in her pouches grow colder as they turned to ice inside it. Quickly bending them back to their liquid state, she kept her eyes on the firebender in front of her.

"If I fall, you may try. Or if she breaks the rules. But she won't! She knows that doing so means giving up her right to the throne. Katara, my… Azula will fight tooth and nail, but she will follow the rules… Even if she seems rather deranged at the moment." That last part, the prince spoke with a voice that sounded… off. But Katara understood. As he had explained, he mourned the fact he needed to kill his own sister. But he knew that there was no other choice.

"Oh, she will." Katara whispered, eyeing the princess who stood at the foot of the grand staircase leading to the Fire Temple, "She knows that if Aang defeats Ozai, there still may be one small chance for her to get out on top."

And indeed, it was a dangerous bet… But one the waterbender was willing to take. Azula had proven herself to be quite obsessed with something when she had a plan. Katara had seen it in Ba Sing Se, and again in the Air Temple. And she guessed that Azula's wish was, above all, to have power. Real power.

And she could only achieve that by becoming Fire Lord. But to do so, she needed to eliminate the two threats to her accession: Zuko, who had the better claim, and Aang, who would stop her in the name of peace.

To stop her brother, Azula would have to kill him during this blasted Agni Kai business. But to stop Aang, that was a whole different story. To do that, the princess would need her. And Azula knew it. Hurt her, and Aang would come for her, without a second thought. But to capture her, that would mean a rather subdued Avatar.

So, Katara knew that to set Azula off balance, she needed to bait her into breaking the rules of the Agni Kai, making sure that she herself could join the fight without breaking the sacred laws herself. They needed to bait Azula.

"Zuko. Listen to me. You need to make her think that Aang has already won. She needs to think that to become Fire Lord, she will have to face the Avatar. She isn't afraid of you, but seen her… appearance, I would say she has lost some touch with reality. If you can upset the delicate balance of her mind…" And not for the first time that night, Katara felt a slight pang of pain in her heart for Azula. She didn't want to. But to see those eyes so broken, it seemed that something traumatic had happened…

But she had killed Aang. She had threatened her with unspeakable things. No mercy. Not tonight.

"Are you out of your mind? If she thinks Aang will come after her, she will double her efforts to kill me! Which are already going to be rather substantial! And if she thinks Aang has already managed to defeat our father, she will… she… oh Agni, are you really hoping she will attack you?" Zuko groaned that last part, clearly not happy about the idea.

"Yes! I suppose that will be considered as breaking the rules, yes?" The waterbender saw that the Fire Sage seemed to finish his prayers.

"Yes, but Katara, if she attacks you, and wins… All our efforts will be in vain! Aang himself told me that if it was the world or you, he would choose you! If you lo-"

"Come on Brother!" Azula spoke up, in a soft singing voice, "It is time!"

Katara watched as the prince pursed his lips, sighed, and turned around. In his eyes, in was clear that he didn't want to do this. That even with all his talk the last few days and even weeks, he didn't want to kill Azula. And the waterbender didn't like that. Zuko was more than capable of killing someone, she knew that. But to kill his own flesh and blood? No… She supposed no one was really quite capable of that. At least, not someone who was sane. The princess, however…

Looking as Zuko took a few steps into the plaza, Katara observed Azula. She seemed to have lost any touch with reality, her ember eyes flying left to right. Azula cocked her head to the left, then to the right, as if she was listening to someone. Then, it hit her.

During the aftermath of the siege of the North, Katara had helped Yagoda with the wounded. Some, those who had been on the Outer Wall and had faced the brunt of the Fire Nations attack, had apparently seen horrible things… And they had gone mad even if it was just for a moment. She still remembered the line of soldiers, covered in burns and with wide eyes, the white standing out in the ash-covered face. They had been mumbling and screaming, answering people who had not been there… And the look in their eyes, the small gestures… It was exactly the same as the look on Azula's face at this moment…

No. She couldn't feel pity for her. The princess, even in her state, was not a nice person! She had killed Aang, brought misery to so many people! And she needed to pay for that, crazy or not. She had committed those atrocities when she had been quite sane. So, no. No pity.

Checking over her shoulder, past the great iron gates of the plaza, if Appa was still safe, Katara began to walk towards the great columns lining the square. She kept her eyes on the two figures that were moving towards the centre, while the Fire Sage was quickly moving back towards the temple. Arriving at the middle of the column lined corridor on the left, Katara decided that this was the best place to watch the fight. She would be close enough to help if needed… And normally, the fire wouldn't be able to reach her here.

"I'm sorry it has to end like this Brother." Azula spoke loud enough for the waterbender to hear, but she strained to hear the answer Zuko gave.

"No… You're not." She saw how he slumped his shoulders, as if it made him terribly sad to even consider what was to come. Katara let her own blue eyes flicker towards the staircase leading up to the temple. The Fire Sages were running inside, and that made her pause. Were they afraid of what was to come.

Then, the entire plaza lit up in an inferno. The waterbender managed to duck behind one of the pillars of the corridor, but even so, she felt ash and soot rain down on her as the fire consumed as much as possible on its path.

There were blue flames, clearly those of Azula… But the orange and red flames, tinged with green, blue and white, were definitely more powerful. As the flames died down, it seemed there was a pause, and Katara glanced past the column. The smoke, black against the dark orange sky billowed up from the marble square, where a great dark patch of ash showed the point of impact of the two attacks. Looking further, the waterbender saw that Zuko was still standing, even though the buildings behind him were burning in the blue flames of the princess. Then, she let her eyes wander towards where the princess was standing.

She too was still alive, but was evidently shaken. Katara saw how the right-hand was twitching uncontrollably, while the lips of the princess were moving, even though there was no sound coming from the dark red lips.

"Azula… It is already over. The Avatar has won, and is coming… Please stand down." Zuko's voice rang over the eerily silent plaza. Sure, Katara knew that it was a lie, and that there was no way of knowing if Aang has indeed done all that… But she had to believe that. And Azula had to think it was true.

"Zuzu, you were never the best liar! Father will have killed the Air Degenerate by now." Azula answered, with a crazy laughter following her words. Katara balled her fist, as she quickly retreated behind the column once more as flames appeared. No. Aang would not have lost. She knew he had not. Surely… Surely she would have felt that… Her heart would have shattered the moment Aang would have fallen…

Blue flames lunched from the other side of the plaza, and as Zuko deflected them, Katara could see that the princess had propelled herself with the help of fire towards the prince. Pursing her lips as not to shout a warning, the waterbender realized that even trying to warn him would probably be considered breaking the rules.

Zuko was prepared, however. Each attack was blocked, or he moved out of the way of the flames. Katara hated it, but she still hid behind the column. One firebender, she could probably deal with… But the two on the marble floor were clearly not trying to limit the damage they did to their surroundings… The temple was burning, Fire Sage running out of it… Flames had hit the iron gates, and she saw that the fire went out in an instance, probably because Appa had bent the air out if it. The bison was afraid of it… So he would probably stay away… She hoped.

There were also flames on the colonnade on the other side of the plaza, making her suppose that her own hiding place was probably also burning… Gritting her teeth, she knew that the only "safe" place to be now, was close to Appa. Tui and La, why had Zuko accepted the Agni Kai challenge? Both of them could have taken down Azula! But even in the state she was actually in, she seemed more than a match for Zuko. Even though the prince was calmer and more precise, Azula's crazy attacks would penetrate his defences one moment or another…

Peering past the column, she saw that the two had moved towards the opposite side of the plaza. Taking a breath, Katara began to run as fast as possible towards the gates. From there, she had a better idea of the general battle, and she would be out of the burning buildings. As her feet hit the ground, she heard soft rattling. Quickly glancing down, the waterbender was surprised to see iron grates. And under them…

Water.

Spirits, she had an enormous bending source…

Why the fuck had Zuko accepted this stupid idea! With this amount, she could have easily beaten Azula! Quickly looking at the fight, she saw that blue flames encircled the prince, while red flames appeared from the ring, as if to keep Azula's flames at bay. As Katara managed to reach the great gates, she glanced through them. Appa was standing a few yards away, eyeing the fight suspiciously.

Having been satisfied that the bison was still safe, she turned back to the fight.

Well… fight…

The flames had died down, and suddenly, she heard a body hit the ground, and a soft grumble.

"Azula, stop!" Zuko spoke above the dying sound of the fires. At he didn't sound wounded or hurt… So… Had that body been… Azula's?

"Father named me heir. He disinherited you! You were removed from the scrolls, just like the traitor Un- Iroh!" Azula's voice hissed, and as the smoke cleared, Katara saw the princess standing up from the ground where she had fallen. There was now a space of about thirty feet between the two siblings, and the fires didn't reappear. For some reason, the eerily silence was much more dangerous than the sounds of battles.

"And you don't think he will do the same to you?" The prince asked, his words sounding much harsher than they had previously done. Katara closed her eyes for a moment. Azua had sounded a little vulnerable just before, but she had understood the implication of the princess's words. Azula was trying to make Zuko angry by speaking about their father.

"See Zuzu… the difference between you and me is that Father actually loves me." As Katara looked on, she saw how Azula jerked her head to the right suddenly, and after a few moments, she whispered, "You don't know anything, you went away!"

The waterbender felt that slight pang of pity once more. Obviously, Azula had answered… Whatever she had heard.

"Azula." Zuko's voice was hard, "Get a hold of yourself. Get up and admit your defeat. Die as a princess."

Katara realized that the prince wasn't seeing what was plain or everyone to see… That his sister had gone mad, and that no reasoning was possible… And the scene was absurd. She should be shouting out for joy because they were moments away from being rid of that bitch.

Taking a step forwards, onto the plaza, Katara stopped in her tracks. No interfering… Nothing. No shouts, no help. She could not do that. If she did meddle in Zuko's favour, the Agni Kai would be declared over, with Azula winning… And then, she would be the legitimate Fire Lord… So even if Katara wanted to put a stop to this… She couldn't.

"What, and letting you kill me?" Azula's voice was suddenly back to the cold and precise manner she had always spoke in, "You know, even Mai didn't die with her head high. She begged."

Closing her eyes for a second, Katara knew that was exactly something to make Zuko waver. He had spoken about the girl Mai on the way here… Shit. Glancing towards Zuko's back, she saw that it was rigid and straight, and his fists were balled and shaking. Shit, shit, shit.

"I guess you are afraid of me. You don't know what I'm capable of anymore." The prince's voice was cold, colder than Katara had ever heard it. And she knew that, if she had been able to look in his eyes, she would have seen the angry scowl he had sported during the months he had chased them all over the world.

Azula's ember eyes suddenly turned to her, all the madness gone. Katara kept her own gaze steady, but it was unsettling. For one moment, she had felt pity for the princess… But now, hate was churning in her stomach, ready to explode.

Stop talking to her Zuko. Kill her and be done with it.

"You haven't even tried lightning! Then again, you need a clear mind to do so… Maybe you are just mad. Or you are afraid I will redirect it." Zuko taunted her, something Katara could have appreciated… If it was not for Azula's look.

"Oh… You want lightning? I'll give you some." With that, the princess dropped a hand towards her right foot, pulling it it a wide arc. The sizzling sound of the lightning… The sound Katara hated so much… Could be heard over the plaza, and she saw that Zuko positioned himself in a stance she had seen him teach Aang.

But even so… Katara watched the ember eyes of the princess. And she saw only one thing. Pure loathing. Loathing for a brother who apparently had something she had not known. Perhaps even loathing for Katara herself… Why, the waterbender could not imagine. She had never been the one to hurt Azula. But still, she observed the slight change in the princess's stance.

"No!" Suddenly, Zuko lurched to the right, Katara felt the hair on her arms stand up, as the electricity of the lightning was bent out of Azula… Towards her. For an instance, fear gripped her heart. That had been Azula's plan. Hurt her.

But before the lightning could even reach the middle of the square, a shadow passed in front of it and was hit by it. The horrible smell of burning flesh was suddenly everywhere… And as it hit her nostrils, Katara knew. Zuko had taunted his sister to make a mistake… Not to be cruel. But he had not foreseen this. So… Tui and La, he had thrown himself in front of it…

"Zuko!" She shouted. The rules be damned! She needed to help him… Because he was her friend. A good friend actually. That surprised her, even though she had realized it before. Zuko may be gruff, rude and rather solemn… But he cared for them, in his own way.

Blueish light chased the orange tinted dark sky away for a few moments as a great bolt of lightning shot out of the still outstretched hand of the firebender. She didn't care for the rules of the Agni Kai, she needed to help him.

And suddenly it hit her. She was now the only one who could stop Azula. And the thought made smile. The princess had said that her fight with Zuko was the showdown that was always meant to be… Well, she was going to be surprised. For killing Aang. For killing so many innocent. For letting them fail in their invasion. For having tortured Suki. For, apparently, killing Mai.

For all that, she was going to pay. Mad or not. Those crimes had no excuse. And if Azula was to be punished, Katara thanked the spirits that it was by her hands.

"K…Katara! She…" A coughing fit, sounding rather painful, could be overheard from the smoke, "She broke the rules!"

Zuko was alive! And… If that was true, he was the only legitimate Fire Lord now! Spirits! That would mean Azula would do anything in her power to kill him!

Running towards what she supposed was Zuko, blue flames suddenly roared towards her, making her jump to the side. As the smoke cleared, Katara could make out a shadow on the plaza, moving towards her at great speed. Shit!

Swirling towards the colonnade of pillars where she had hidden before, the waterbender knew that if she had ever been in mortal danger, it was now. But her mind was so… so clear. There was only one thing to do. Fight. And fight. And not die, of course.

As she ran, she heard a strange cackle behind her. Quickly looking over her shoulder, Katara realized that that had been Azula… Spirits.

"Zuzu will be cared for by our own physician, if you don't mind!" In this case, the waterbender supposed that physician meant executioner. At the same time, she saw Azula make the same movement as before. Stretching her own hand, Katara felt the familiar pull of the water in the canals underneath the grates near the columns. Balling her fist, she lifted it out of the canal and threw it backwards, freezing it, just a bit. Quickly disconnecting the water from her fingers, she knew that lightning would follow the water towards her. So, she couldn't give Azula a chance to make this easy.

No. She was not going to make this easy.

Reaching the colonnade that was still burning, she ducked behind her old friend the pillar. Just in time, as blue flames roared past her, destroying a part of the wall at the end of the building. As she kept an eye on her left and right, Katara began to move her hand in soft circles, finding the water underneath the plaza. The liquid closest to her, she began to freeze parts of it in long ice spikes, thin enough to be razor sharp. Inhaling softly, she waited for a small lull in the fires. As the blue flames died down, Katara stood up. A waterbender would stand.

She was not going to die crouching behind a pillar.

She would not die.

She was going to take revenge for so much hurt and so much injustice.

Punching her hand towards the rooftop where she had seen Azula last, she let the water, filled with the small ice spikes fly towards it. The impact was so great that the roof collapsed under the pressure. But no Azula…

Suddenly, on the ground below her feet, Katara saw a soft blue glow, and turning around, Azula stood just a few feet away from her, with a rather pleased smile.

"Water bitch." The smile widened as flames appeared in her hands. Shit.

Katara ran. It was perhaps not the most glorious thing to do, but rather live as a coward for a second then not live at all. Pulling the water out of the fountain on the corner, she searched around her. The colonnade on the other side of the plaza had partially burned but seeing one part still intact made her think. If she could lure Azula into it, plant an ice spike between her ribs and disappear once more into the shadows… It would perhaps not kill her, but it would significantly weaken her.

Freezing the water underneath her feet, she let the ice slide her towards the other side. Swirling to the left and right, she heard explosions and the crackling of flames behind her. No time to look behind her! She needed to get to the other side. As she managed to finally reach the other side of the marbled plaza, Katara quickly glanced towards the small bundle that was Zuko. She saw a hand move, so at least, he was alive…

Bending the water into a hard ball, she hurled it towards the princess, who would need to escape it by veering off course. Splitting the ball into three, she punched the two new spheres towards the left and right. The soft crunch coming from the left made her think that she had at least hit her.

No time to check.

Flames appeared, and as she needed to jump out of the ways, the waterbender fell to her knees on something metallic. Glancing down, she saw that here too, there were those canals covered by the grates… Spirits. If she could get Azula her, she could impale her by using an enlarged ice spike, driving it up from the water into the firebender's body.

Smiling at that idea, Katara got up.

You are not a monster my love… The words, spoke by Aang nearly two months ago… After Hama… suddenly hit her. Katara tried to push the thought away, as she needed a clear head… But the words still echoed in her mind. It was not monstrous to kill a killer… Was it?

"What did you feel when you did it?" He had asked… And she had answered truthfully…

"I felt disgusted! Afraid! Powerful and evil!" Was that… Was that what she would feel like?

"Katara… Being capable of evil doesn't make you evil. Otherwise, I would be evil too. And Toph. And Sokka… Everyone would be evil, the moment they bend something, or take up a sword. Does it make us evil? No. Our choices make us evil."

Was it her right? Was it her choice to kill Azula? No… she had made that vow in anger and despair when Aang had been wounded. And the princess deserved so much more… But as Zuko had said too. She had hurt so many people, they she would have to get in line. So many more people deserved justice…

And if she gave in to that kind of revengeful hatred… She would be no better than Azula. Looking around, Katara saw some chains.

Imprison her. Let her be trialled for what she had done… Aang had the right to decide what was to be done to the Avatar's murderer. Zuko had the right to judge the actions she had committed against him… Suki had the right to punish Azula.

It wasn't mercy. Oh no… No, this was giving Azula something else. A just punishment. Exhaling softly, she stood up. Katara was ready. Let her come.

Answers:

Guest : No, I will not follow the comics (by a long shot lol!) But will make it a whole different story. And Azula… Well, I would love to delve deeper into her mind, as I don't consider her evil. She was indoctrinated and had some flaws… But she didn't have someone to guide her or even extend a hand in friendship, like Zuko had.

Jjsmith103 : I always pictured Aang being a whole mess, cursing all the way, while someone like Katara would be more like "Alright, die b*tch."! And indeed, I haven't written it yet (next chapter is back to Toph), but I have some ideas!