"Do you still think it's a good idea?" Celestia asked her younger sister. The two were sitting on their balcony, talking about the final day of the tournament. It was about half an hour before the last duel started.

"Tia..." Luna sighed. "I must do this, and I know what I'm doing, truly. Trust me, it would work just as I had explained to you earlier."

"I sure hope so." the solar alicorn frowned slightly. "But what about Sirius? Is he going to be alright with it?"

"I don't know... For him, it might be a possibility to vent off his frustration with me." the younger princess explained. "And for me, it will be a release of my own emotions. I know you want what's best for me, but I have to do this."

"..." Celestia let out a long sigh. "I hope you are right, Luna." she looked at her sister. "I always have trust in you, but I'm worried."

"I know, sister." Luna replied. "And I'm truly grateful. But it must be done."

Sirius was ready for the final duel. It was what he thought would be an ultimate test of his capabilities — a duel unlike any other he had ever taken part in before. It was thrilling, it was exciting, and yet it was also fearsome — what if he failed? He banished the thought out of his head — he wouldn't. He had gone through the best of the best, he climbed from the bottom to the top all by himself. He was going to tackle whatever waited for him. He was going to win, too. Nothing less.

Before the duel began, he warmed up by stretching and galloping around, making sure the blood flowed perfectly, allowing him to move fast and precise. He checked his swords for edge damage — there were some minor issues he would have to deal with later, but nothing alarming or in need of his immediate attention. The dents in his armor were fixed, but Pride Fight said that the armor would have to be replaced — it was getting too old anyway, and a good thrashing would most likely destroy it completely. However, the old stallion was proud of the fact that such a good warrior like Sirius was wearing it to battle.

After checking all the straps and making sure they were perfectly buckled, Sirius went to the arena. He was informed of the rules of the duel — only one hit to the exposed part of the body. Thus, his most vulnerable spot was his neck. There were also his legs, but they were harder to get.

The club members followed him since they needed to take their respective places on the tribunes. All of them wished him good luck. He nodded politely, but he knew that there was no such thing as luck, and it certainly wasn't by his side the most of his life. He didn't believe in luck — he trusted in his skill. He would never believe in a construct created by an intelligent mind. Such things tended to fail just as often as the minds of their creators did.

Finally, the former human entered the arena. He was very surprised and confused by its look: there was a thick fog lying across the ground, concentrating at the opposite end of the arena. Sirius frowned — he didn't expect it. What was it? A disorientation trick? Was he going to fight the fog? It didn't make sense to him. Though, it could be just a fancy effect for an introduction. He decided to stick with the last option and see where everything was leading to.

He stood at one end of the arena, the one that had less fog, and waited. He glanced at the highest balcony. Sirius noticed how nervous Luna looked. Celestia looked just as, if not more so nervous than her younger sister. Both were looking at the fog.

Sirius became slightly worried — who was going to fight against him? Who was the one the princesses of Equestria, both powerful alicorns, were so nervous about?

"Finally, the duel will begin!" the announcer spoke, immediately gathering all attention. "This time, Sirius stands against a peculiar opponent. Powerful and strong, she is more than a match for him. Introducing — Nightmare Moon, the queen of darkness herself!"

The crowd gasped, looking at the fog veil as a tall equine figure stepped out of it. Black as the darkest night, clad in ceremonial blue steel armor, slit-pupil eyed, slim alicorn mare appeared on the arena. Sharp fangs could be seen peeking out of her mouth as her aqua eyes looked at her opponent. Her raven-like wings were spread regally as she proudly walked out of the thick fog. A big sword was being levitated by her side. It was no regular sword, not even a longsword — it was a greatsword, one of the biggest of its type. More than two meters long, it almost came to the length of a spear.

Sirius frowned. She had armor only as a breastplate, hoof guards, and a helmet. However, he was sure getting her would be very difficult.

"Ah, you all insult me by placing me against such a pitiful little pony!" Nightmare Moon said with anger in her voice, mocking Sirius. He immediately drew his weapons out. "What is that he is holding? Toothpicks?" she guffawed. "Oh, my... Such a pathetic fool... This is the true sword." she levitated her greatsword in front of herself. "Oh, Sirius... Such a good name for somepony who shall be under my hoof very soon! Thy weapons are way too short for my liking." she grinned. "My sword is what holdeth true power — the power of the moon!"

The greatsword started glowing, just like the moon. The pale light spread throughout the blade, making it glow eerily.

"This is the Greatsword of Judgement." Nightmare Moon declared. "And now, it shall judge thy worth, Sirius!" she saluted. "Once thou art defeated, I shall plunge this world into eternal darkness, and only one true light shall shine — the moonlight!"

Sirius tightened the grip on his swords. It was going to be a fight unlike any other. He analyzed his opponent. She was an alicorn, meaning she could fly as well as use magic. Her voice was slightly familiar, but he couldn't quite place it yet. Then, her special mark caught his eye. It looked identical to Luna's.

The former human looked at the nightly princess. There was something hidden behind her eyes... Fear. Regret. And... Something else.

As Nightmare Moon approached Sirius slowly, and yet putting power behind her regal steps, the orchestra started playing a song.

https://youtu.be/Tl2NfsblnZs

"O-oh, majestic!" Nightmare Moon said, laughing.

Suddenly, she lunged forward, closing the distance between her and Sirius in one swift motion of her huge wings. She thrusted her sword, but her opponent managed to evade the hit by dodging to the side. She immediately followed by swinging her greatsword. Fortunately, Sirius parried the hit and tried to land his own, only to meet her blade once again.

Sirius grunted, and tried to stab her with his shortsword. However, Nightmare Moon caught it in her magic and threw away. The blade flew through the arena and managed to get stuck in a wooden wall that separated the tribunes from the field of battle.

"Oh no, thou shalt fight with only one sword, little pony." the alicorn of darkness taunted him.

Sirius jumped away just in time to evade another hit. The alicorn was unrelenting: she struck fast, trying to get to him. The former human had to use his sword to block and deflect the hits. He couldn't riposte without being hit, and thus tried to find an opening for him to strike.

However, it seemed like luck wasn't on his side. So, he had only a few options to choose from. He decided to at least bring the battle to equal grounds. He started trying to hit the alicorn mare with his sword. She blocked his hits, but the battle was no longer one-sided.

The two exchanged hits for a few moments before Nightmare Moon used her wings to glide to the side and attempt to take Sirius by surprise. It almost worked, but her sword met his armor. The force of the strike dented the armor and almost made Sirius fall. However, he managed to retaliate and deflect the next hit, albeit barely — the armor restricted his movements, mostly his right foreleg.

"Thou shalt not win, fool!" Nightmare Moon taunted him. "I had decades of training, and thou hast lived a little more than a decade. Thou art not a match for me, not by the long shot!"

Sirius didn't say anything, focusing on delivering hits instead. The battle was fast-paced, his speed and agility matched by his opponent's skills and characteristics — they were fighting almost equally.

Suddenly, the alicorn discharged a blast of magic, sending Sirius flying across the arena. The crowd gasped as he hit the wooden wall and fell to the ground, his armor almost completely in ruins. Even with the spell going, he was confused. The force of the hit was very hard, making it hard to return to the senses.

"I am more powerful than thou shalt ever be!" Nightmare Moon declared. "Surrender whilst thou hast a chance and join me! Such a warrior must not be wasted in the sunlight but serve the moonlight!"

Sirius stood up slowly, his dizziness fading. Thankfully, he still had his sword in his magical grasp. He undid the buckles and took off the armor, leaving only a gambeson. It was torn slightly, but still functional. He also left his helmet on. The crest was dented and almost broken off, but he still needed protection.

"Oh, undressing already..." the alicorn bit her lower lip. "Are you surrendering your body to me?"

Sirius snorted, getting dust out of his muzzle. Then, he raised his sword.

"Pity the fool, for he hath sealed his fate!" Nightmare Moon declared, and then propelled herself forward by a powerful wing flap. She extended her sword, preparing to pierce Sirius.

Sirius dodged to the side, his opponent's sword cutting the side of the gambeson but not getting the body underneath it. The colt acted swiftly and followed his dodge by a downwards cut. The mare deflected the blow, forcing him to step back and retract his sword to parry her own hit.

The former human couldn't figure out how to beat his opponent. The alicorn was agiler, had more speed, and was certainly stronger than him. However, he wasn't going to give up. He wouldn't surrender — he must win.

Finally, he managed to land the first hit, slightly denting the side of Nightmare Moon's helmet. She shook her head and used her magic to push Sirius away before he could strike again.

"Impressive." she admitted, looking at him.

Sirius went forward, swinging his blade. The hit was blocked and riposted, leaving him but a millisecond of time to either block or deflect it. The tip of the greatsword went over his fur, barely touching it. He didn't give up and went in for a stab, trying to thrust at the mare's neck. He didn't succeed but was very close to it.

Meanwhile, everyone silently observed the battle. To them, it was but a blur and sounds of clashes that overpowered the raging music. Celestia and Luna were particularly impressed. The nightly alicorn wasn't sure Sirius would be able to hold on for so long. She had summoned an image of her darker self. She conjured a phantom of herself, of who she was just before her battle against her own sister a bit more than a thousand years ago. She and her fighting skills were in their prime back then.

Luna couldn't believe her own aggression was matched by Sirius'. He fought without holding back, and she could see he was going for especially deadly moves. If not for Nightmare Moon's magical prowess that was further fueled by her emotions, and if the spell wasn't up, Sirius would most likely pierce the neck or cut the head right off the body, which would be a gruesome and gory display.

Suddenly, Sirius was knocked down by a powerful magical blast. He dropped his sword, leaving himself completely defenseless. Nightmare Moon picked up his sword before he could do it, and then levitated him up by the neck. It didn't hurt, but the former human certainly didn't like being used as a toy. He bared his teeth, anger in his eyes.

The song silenced, coming to a stop, and only the booming silence remained.

"Well, now..." Nightmare Moon laughed. "It seemeth thou hast lost, Sirius." she crossed her own sword and his, making a scissor-like combination of blades. "Admit it."

He struggled against the magical grip, but it was futile. He frantically looked around, searching for a way to divert the alicorn's attention.

"Admit thy defeat, and I might spare thee." she taunted. "Afraid, art thou not?"

Sirius found something. It was his shortsword, stuck in the wall. He needed to get it out.

To distract the mighty alicorn, he used a portion of his magic to push the blades away from his neck.

"Oh my, still struggling..." Nightmare Moon giggled. "It seemeth the battle hath left thee powerless. Thy powers are weak, foal. Surrender to me."

He took hold of the shortsword and tugged it. It was firmly stuck in the wood, but he didn't give up, pouring more power into his grip.

"Only a few words..." the alicorn whispered to him. "Admit thy defeat. Thou canst not run, thou canst not fight. I may grant thee mercy, but only if thou submit thyself to me."

Princess Luna leaned in, noticing something. She saw how Sirius struggled to get out the shortsword. However, she feared he wouldn't be able to do it. It seemed her darker self had gained the victory. Luna's ears dropped, sadness showing on her face in a frown. Was the darkness truly that strong?

Finally, Sirius got the blade out of its wooden confines. He pulled it, turned it around, and aimed for Nightmare Moon's neck.

"Why art thou silent?" she demanded to know, anger flaring in her voice. "Canst thou not see? The night reigns now! Submit thyself to it, or be burnt into the sun thou so likest!"

Sirius sent the weapon flying towards the alicorn. The shortsword went right through her neck with its tip forward and then landed on the ground nearby. The colt blinked in confusion — wasn't it supposed to be either stuck in her or bounce off her neck?

Nightmare Moon's eyes widened in surprise as she looked at the sword. Then, her eyes returned to Sirius. A grin appeared on her face.

"Most impressive." she said before disappearing in a puff of black smoke.

Sirius fell to the ground, the air knocked out of his lungs. He slowly got up and looked around. His opponent was gone, both his swords were lying nearby.

There was something else, however. In the place of the dark alicorn, a sword was hovering above the ground. It was the greatsword Nightmare Moon used against him.

He warily approached the greatsword. His magic wrapped around it and brought it closer to him. There was no resistance. Surprisingly, the sword seemed to be lighter than it was. The crescent-shaped crossguard and the pommel were decorated with carved ornaments. There was also a round blue gem inside the pommel, reflecting the light in a beautiful way. The blade was straight, tapering towards the end nicely in a more thrust-oriented fashion. It also featured two fang-like protrusions closer to the guard. The part of the blade between them and the guard was unsharpened — it was the ricasso. The sword was finely balanced for its size, and it was definitely suitable for fencing.

Sirius raised his new sword in victory. He won. The audience erupted in cheering, adding thunderous applause quickly after. Even the princesses bore smiles on their faces and clapped.

It was a meaningful day for the former human. Not only he defeated everyone in his path and was rewarded with a grand amount of money, he also beat a very powerful being comprised of dark and negative emotions. Such a victory gave him a new weapon. As Nightmare Moon called it — the Greatsword of Judgement.

Sirius had proven his worth indeed.

Author's Notes:

I bet you didn't expect Nightmare Moon to show up, did you? Even as a phantom, a mere image conjured by Luna, she is still very powerful. If not for her own love of gloating over her victories, Nightmare Moon would win. It could almost qualify as a clichè defeat, but I decided to go with it because I'm certain it's how Luna would imagine her own dark self to be.