Kazuki was walking around the convention looking for something to do since he and his sister came here to have some fun with their friends. This was a small convention so it didn't have as many people as a really big one, but it was still fun to hang out with his friends here, they went to different places to see what they could find. He was cosplaying as an OC from the Ōtsutsuki clan from the anime Naruto, he already had a slender figure thanks to years in his school's swimming club, good thing he was thinking of becoming a professional swimmer.

Kazuki's cosplay consisted of a traditional white kariginu(狩衣, hunting robe) with a row of tomoe(巴) running down the centre, around the collar and near the edges of the sleeves that were adorned with intricate gold and purple lines, white baggy pants with a vertical row of tomoe(巴) on each side, a pair of black tall geta(下駄, wooden sandals) with two ha (歯, teeth), a pair of white tabi(足袋, socks), and a pair of black gloves on each hand for clothes a white wig for his hair, makeup to make look like he had white skin with a third eye on his forehead and colored contact lenses to make his eyes look like the Byakugan (白眼, White Eye). Also, he chose to not have horns because it would cause too much trouble.

As Kazuki walked he spotted a stall with someone cosplaying as the Merchant from Resident Evil 4, the stall itself had many items of many franchises and they are all surprisingly well made and accurate. So he approached and greeted the Merchant.

“Welcome Lord Ōtsutsuki,” said the Merchant as he recognized Kazuki's attire.

“I must say it’s a very good costume you have and all those items are very well made,” said Kazuki as he saw the items on sale.

“Thank you, I made everything that is for sale here,” said the Merchant with pride in his voice.

“So you make props, do you have a studio or something like that? Because those items are too well made to sell on a small convention like this one,” said Kazuki as he assumed that the Merchant was an artisan or something similar.

“Well I just like to pay attention to the details, besides any convention is a good place to sell my ware,” said the Merchant as he tried to downplay his role in the creation of the items, so he asked, “So who are you anyway? I can tell that you are a Ōtsutsuki, but that’s it.”

“Oh, that is an original character. He is a Ōtsutsuki that bothered to train and is a capable warrior instead of just rely on his overwhelming power and chakra, but I have to admit that I used Kaguya and Momoshiki as templates,” said Kazuki a little embarrassed at his lack of creativity in the design, but it was to be expected since they all of them seem only to used mostly white traditional Japanese clothing.

“So, is there anything you would like to buy?” asked the Merchant curious.

As Kazuki looked at the items he saw many things he wanted to buy but also remembered the rumors about cosplay disappearing in conventions but he thought that they were just rumors.

“Do you have anything from Hunter x Hunter and Type-Moon?” asked Kazuki unexpectedly.

“Not something from Naruto,” said the Merchant in surprise.

“Well these are among my favorite animes, I especially like the Mahō (魔法, Magic/Sorcery) and Majutsu (魔術, Magecraft) in the Nasuverse and the Nen (念, Mind Force) abilities in the Hunterverse,” said Kazuki as he looked for items to buy, but then he got a idea so he asked, “Would be awesome if you had a book with many forms of energy manipulation, functional magic, technology and other forms of information all written in the language that could only be read by the user of a Rinnegan (輪廻眼, Saṃsāra Eye) and Byakugan (白眼, White Eye)?”

“Wait here for a moment,” said the Merchant before he went to the back to look for something, only to come back about ten minutes later with a book.

Kazuki looked at the white book and he got a “Tome of Eldritch Lore” vibe from the leather bound book with an unreadable title, the sealing like inscriptions on the edges and different cursed seals in the free spaces.

“What is this?” asked Kazuki.

“Ironically, exactly what you asked for. It was made for another client but he doesn't want to purchase it anymore,” said the Merchant as he placed the book on the counter.

“May I?” asked Kazuki and the Merchant nodded.

Kazuki opened the book and all the pages were filled with the same unreadable language from the title that he recognized from the movie. The only reason he knew that it had information beyond the Narutoverse was that he also recognized the diagrams from other mangas and animes explaining different powers.

“You are so lucky that had this on storage. What are the chances?” asked the Merchant as he made sure to not give away that he just made the book.

“How much?” asked Kazuki as he closed the book.

“A 100 bucks,” said the Merchant.

“Well, it’s really well made. Sure,” said Kazuki as he paid the Merchant.

“Thank you, have a nice trip,” said the Merchant as he waved at Kazuki.

“Wha-” started Kazuki before everything went blank.

Thousands of years later

Ōtsutsuki Kazuki was fly over Canterlot and landed on the Castle's garden in front of a statue of him, or more specifically his original body turned into stone, luckily he could leave his body at will since the soul of a Ōtsutsuki was capable of existing without a body. His body was just standing straight with a stoic look while his arms were hidden by the sleeves of his kariginu.

Kazuki, unfortunately, had a misunderstanding with the princesses a few years after he arrived, which resulted in a battle where he was defeated and sealed. The worst part was that at one point in time he called them his friends. Worst still they took his book and even after millennia they haven't found a way to read it, all those that went mad trying didn't favor his reputation and neither did those that died.

Fortunately, after few months, Kazuki learned how to leave his body and later possess the body of others but he wasn't cruel enough to just assume control of the body of another without a good reason. Inspired by Kurama from Yu Yu Hakusho, he instead possessed a young female and waited without taking over for her to conceive a child so he could create a body without developing a soul.

It wasn't easy to create a less volatile version of Reika no Jutsu(霊化の術, Spiritualisation Technique) to not kill either his surrogate mothers or new bodies. However, he managed to do just that and thus he created another method to body jump.

The result of body jumping was that he lived many lifetimes as many different species and he learned much in these years, the only thing he didn't manage to accomplish was getting his book back.

Unfortunately none of his subsequent bodies were as strong as his Ōtsutsuki one, at least they were similar enough to him seeing that this world was of the anthro variety, some came close but not quite there yet and because of that he had to seal most of his power every time he reincarnated, at least he learned how to control most of his powers.

Kazuki managed to read a few pages of the book before he was sealed so he developed nen and magic circuits as well and in the time between incarnations, he would integrate and modified these powers. He can't wait to test them once he was freed.

Yesterday he saw Twilight and Spike leave to oversee the Summer Sun Celebration in Ponyville, good thing he watched MLP:FIM. He never thought that what he remembered from the show would be useful like this. The return of Nightmare Moon is a good opportunity to free himself if he miss this opportunity the next one will only present itself on Discord’s return.

Kazuki, in spiritual form, sat in lotus position he floated in front of his statue and waited. He didn't have to wait longer than a few hours before he felt the Natural Energy (自然エネルギー) of the world shift slightly, so he looked at the moon and saw four stars glow brighter for a moment before the mare’s silhouette disappeared from the moon.

Using this shift in the Natural Energy he entered his body and not long after cracks started to form. Soon after he moved, which caused flakes of stone to fall and not long after he was freed. And for the first time in millennia, he opened his three eyes and looked at the night sky.

“Who is there?” asked a guard as he walked into the garden.

Immediately Kazuki turned to look at the surprised guard that just walked into the garden before he activated his Sharingan (写輪眼, Copy Wheel Eye) and used a simple Genjutsu(幻術, Illusionary Techniques) to freeze the guard in place and erased the last few seconds of his memory.

“The wonders of Genjutsu,” said Kazuki to himself, the first time in millennia that he heard his own voice, the original one. His voice after his displacement was similar to Senju Hashirama the Shodai Hokage.

“Yōton: Gomunawa(熔遁 護謨縄, Lava Release: Rubber Rope),” said Kazuki as he created a very small and thin rope of rubber in his mouth before melting the ends together creating a rubber band, which he used to tie his long, almost touching the ground if it wasn't for his geta, hair into a bun with the rest becoming a ponytail that reached just past his shoulders.

After tying his hair he looked at the pieces of stone, then he used Doton(土遁, Earth Release) and Onmyōton(陰陽遁, Yin–Yang Release) to reassemble the pieces into a statue of him before he fused and reinforced the pieces.

He made sure the statue was in perfect condition before he used the Meisaigakure no Jutsu(迷彩隠れの術, Chameleon Jutsu) to become invisible and the Doton: Keijūgan no Jutsu(土遁 軽重岩の術, Earth Style: Lightened Boulder Jutsu) to float without activating his high-level Dōjutsu (瞳術, Eye Techniques).

After he was off the ground he released the Genjutsu(幻術, Illusionary Techniques) from the guard, he looked around confused before he set his eyes on Kazuki's statue before carefully and cautiously poked it with the blunt end of his spear.

“I must be tired. Maybe I should request a leave of absence,” the guard said to himself when he saw no reaction from the statue.

With that taken care of Kazuki activated his Byakugan to investigate the castle and not long after he found the hidden vault where Celestia keeps the important artifacts. So he floated to that floor height before activating his Mangekyō Sharingan (万華鏡写輪眼, Kaleidoscope Copy Wheel Eye) and used Kamui(神威, Authority of the Gods) to phase through the wall.

Once inside Kazuki deactivated the technique and his eyes to the vault hidden behind the throne and used to look at the door protected by magic as he walked toward it.

Chakra(チャクラ) was made of Spiritual Energy (精神エネルギー) and Physical Energy (身体エネルギー) combined and in balance. Magic –at least the style/form used and understood by ponies– was made mostly of Spiritual Energy and was called Mana or Maryoku(魔力, Magical Energy). Aura (オーラ) was made mostly of Physical Energy and was called Seimeiryoku(生命力, Life Force). So it was possible to use one of these three types of energy manipulation to affect the other two forms. Technically Nen and Ninjutsu (忍術, Ninja Techniques) could simply be considered different styles or systems of magic.

Kazuki activated the Byakugan and the Rinne Sharingan (輪廻写輪眼, Saṃsāra Copy Wheel Eye) to see the inside of the vault and the flow of magic on the door, then he activated the Yomotsu Hirasaka(黄泉比良坂, Underworld Slope Hill) to create a window from the outside to the inside of the vault by connecting to points in space on the same dimension, essentially a portal.

The Ōtsutsuki reached into the black abyss and saw his arm come out inside the vault from a similar window, then he reached out, grabbed and pulled out his book from the vault. Then he closed the window inside the vault. And once the book was in his hands he jumped into the window like portal and came out outside of the castle and deactivated his Rinne Sharingan. Still in the air, he used his Byakugan to look at the Castle of the Two Sisters only to see the mane six confronting Nightmare Moon.

Kazuki kept watching until Celestia was freed and the sun was raised, seeing that Nightmare Moon was defeated he was about to deactivated his Byakugan when he saw that Celestia was looking for something.

“Is something wrong Princess?” said Twilight in concern, the only reason Kazuki knew was that he was reading her lips.

Instead of answering Celestia briefly looked in his direction and Kazuki smile, it seemed that peace didn't dull her instincts. He deactivated his Byakugan, activated his Mangekyo and used Kamui to go into one of his pocket dimensions.

“I can't wait to see both of you again,” said Kazuki before he disappeared in a vortex coming from his right eye, he always liked a challenge.

Somewhere in the Everfree Forest

Kazuki appeared from a vortex before he deactivated his Mangekyo and he stood in front of the Castle of the Two Sisters, now empty. He jumped into the ravine and at the entrance of a cave.

Kazuki entered the cave and saw the Tree of Harmony. He stopped, closed his eyes and stood completely still to gather Natural Energy. After he gathered and balanced the Natural Energy, Spiritual Energy and Physical Energy red marks appeared around his three eyes connected by curving lines.

Now in Sage Mode(仙人モード) his consciousness meld with the forest and more importantly with the nexus of Natural Energy in front of him. The Tree of Harmony was the closest thing to a Shinju(神樹, God Tree) but in harmony, pun intended, with the world instead of just suck the Natural Energy of the world like a parasite to make a “Chakra Fruit" (チャクラの実).

It was not that surprising when you considered that the Tree of Harmony grew from a seed created by his chakra, in a sense, it was an extension of him, like the Everfree Forest that also grew from his chakra.

“Welcome back,” said Kazuki with a sense of belonging as he felt every part of the forest as if it was part of himself.

Kazuki opened his three eyes and saw the Tree of Harmony glow with different colors and hum a calm and relaxing tone, it was a melody of nature, and that made him smile.

He stopped smiling when he saw the marks of the royal sisters, he didn't have a problem with Twilight's mark. Actually, it was the opposite, Twilight has the mark of the tree, but the tree was marked by the energy of the royal sisters when they stole its fruits and that filled him with a sense of anger.

He touched the Tree of Harmony with his right hand and filled the tree with his chakra and purged the remnants of Celestia and Luna’s Magic from the tree. With that done he floated up to the castle’s entrance after he got out of the cave and entered the castle.

Once inside he used his chakra and his magic to carefully remodel and restore the whole castle. In the end, the outside looked just like when the castle was in its prime, but inside he changed the decorations to be more eastern and the banners the once depicted the crest of the royal sister now depicted the Mon (紋, Crest) of the Ōtsutsuki.

After that he used Senjutsu (仙術, Sage Techniques) to create a barrier around the castle, the barrier was made of Senjutsu Chakra to subtly dissuade anyone from approaching the castle and to show an illusion of the still-ruined castle on the outside.

After the redecoration was done Kazuki turned his attention to the small pile of black fur and blue armor, be extended his hands and focused yin chakra on his left and yang chakra on his right.

They manifested as a red flame on his left hand and a blue flames on his right before he combined them over the pile of fur and created a purple 5ft 6in sphere, the diameter being more or less the same as his height without his 4in takai geta(高い下駄, tall wood sandals), with the fur inside while armor remained on the floor beneath the sphere.

With that done he went to the library and places his grimoire on the table before he concentrated a bit of chakra on the tip of his index finger before he touched the cursed seal on the cover.

While he went to look for something to read on the library the cursed seal spread throughout the cover before the title was replaced by a silhouette of a mask, the white was replaced by a gray color.

The eyes of the mask on the cover of the book looked around before it settled on Kazuki, who chose a book and was sitting on another chair.

“Kazu!!” shouted the book with an almost childlike voice as the mask changed to a happy face before it floated off the table and went to be near Kazuki.

“Good morning Hon-chan,” said Kazuki to his friend.

“What are you reading?” asked Hon with curiosity while she floated behind Kazuki and looked over his shoulder. Her mask changed to a question mark.

“Just something to pass the time since I still getting used to my connection to the surrounding forest,” said Kazuki as he turned the page of the book he was holding.

“Ok,” said Hon before she looked around, now with a neutral mask and asked, “where are we anyway?”

“We are in the former castle of the princesses,” said Kazuki as he put the book on the table beside him.

After Hon heard that her mask changed into an angry red oni mask at the thought of those that took her away from her friend, tried to use her before they locked her away when couldn't.

“Where are those hussies?” asked Hon her voice became not only more adult-like but also distorted and more inhuman.

“There is no need to get angry about it,” said Kazuki in a calm manner as he motioned for Hon to come closer.

“Why are you not angry? They kept you prisoner for millennia, they separated us and they stole the fruits of your chakra,” said Hon angry at Kazuki lack of reaction.

“I see no point in hold a grudge against them, it was just a millennium and besides we are free now. While I’m angry that they didn't return the fruits after using them the fruits chose their hosts and I will respect their decision,” said Kazuki in a calm manner but with a bit of annoyance in his voice.

“Why?” asked Hon back to her childlike voice but with a mask that expressed her confusion.

“The Tree, and by extension the Elements, may be an extension of myself but they are also an extension of the land, so if they feel the necessity to chose new hosts then I will accept it,” explained Kazuki to Hon before he added, “Although I’m a bit peeved by the fact that they tainted the Tree of Harmony, it wasn't like they knew about it.”

*Sigh* “Ok, I trust you but if I see them again don't expect me to be friendly with them,” said Hon while her mask changed again this time to show a childish face pouting.

“I know you probably want some time to think about this, so I going for a walk to both relax and to get to know the terrain,” said Kazuki as he got up and did a hand seal.

A puff of smoke later he is wearing a brown traveling cloak with a high collar and a concealed hood, similar to an Akatsuki cloak but plain brown instead of black with red clouds, navy blue baggy pant, black sandals similar to the ones in Naruto and he kept his black gloves. He was shirtless beneath the cloak but had two pouches affixed to his belt, one on each side, with some shinobi supplies.

“Ok, I will summon you if I need. Have a nice walk,” said Hon as she floated off to explore their new home/base of operations.

Kazuki walked out of the castle and headed west to where he felt a large and powerful life form, he kept walking until he reached the entrance of a cave and as he walked in he saw a pair of slitted yellow eyes on the dark background of the cave looking at him.

“Who dares enter my cave?” asked a deep voice from the darkness.

Kazuki's eyes adjusted quickly to the darkness of the cave and he saw a green-scaled dragon with yellow underbelly, the body type was that of a western dragon with four legs in a semi-quadruped configuration, two green wings with yellow membrane on the back near the shoulder blades, a long neck and muzzle, sharp claws and row of teeth, line of spikes from the head to the tail along the spine that were a few shades lighter, two fin-like ears on each side of the head that matched the color of the wings and yellow slitted eyes typical of a reptile.

“Greetings dragon, I was just passing by, I will be on my way,” said Kazuki trying to be diplomatic.

“As if I would believe in such words, especially coming from a pony,” said the dragon with distaste having assumed that Kazuki was a pony from the town near the forest and that he wanted the gold and gems of the hoard.

“I’m not a pony and if you won't let me pass, then you leave me no choice,” said Kazuki as he released a portion of his Sakki(殺気, Killing/Murderous Intent).

Instead of cowering like most being would the dragon saw this as a challenge, an invader trying to usurp the territory he just came into. So in response, the dragon growled and let smoke and fire slowly escape from its mouth. Both of them took a deep breath.

“Katon: Karyū Endan(火遁 火龍炎弾, Fire Style: Dragon's Flame),” said Kazuki after he ended a sequence of hand seals in the tiger seal and exhaled a torrent of flames while the dragon used the flames infused with magic. The two fires collided and pushed against each other. Every time one of them started to gain advantage the other would pour more energy into the technique.

At one point the orange flames of Kazuki became brighter and pushed back the dragon's flames. The dragon felt the flames of the invader wash over its scales, at first the flames were not a problem since dragons were fireproof and the only way to burn a dragon was to saturate the flames with enough heat and/or magic to overcome the species natural resistance that would only become stronger with age, but only an alicorn or an elder dragon can do that.

But then the flames became almost white, which caused the dragon to feel the heat and after that came the pain. Kazuki stopped when he heard the roar of pain over the flames and saw that the walls of the cave, the gold and gems were starting to melt but most of the heat was focused on the dragon.

Kazuki coated his sandals in chakra and walked on the hot floor until he reached the thrashing dragon. The dragon stopped when a sandal touched its sensitive skin and looked at the victor of this dispute.

“You know what that means, right?” asked Kazuki to the defeated dragon.

“Yes, by right of conquest all that belongs to me is now yours, even my life,” said the dragon in a defeated tone for the first time seeing the face of the intruder, now without the sage marks, the hood must have been knocked back by the wind.

“Good,” said Kazuki as he took off his traveling cloak and activated his Chakra Mode(チャクラモード) or Chakra Cloak(チャクラの衣) that it took the form of white flame like energy over his body.

The dragon saw the energy cloak and thought that Kazuki was going to deal the final blow on the loser of this duel. Kazuki saw the dragon with the eyes closed but he had no intention to kill a potential ally, so he made multiple arms of chakra to reach all the burned areas of the giant reptile's body.

“Why are you healing me? You could either leave me or kill me,” said the dragon as the pain faded when Kazuki used Shōsen Jutsu(掌仙術, Mystical Palm Technique) to heal the burns.

“I know the Dragon Code, besides it would be a waste to just let you die, now be quiet and let me heal you,” said Kazuki with a firm tone and the dragon just nodded.

By the time that the walls cooled the dragon was healed and Kazuki was without his Chakra Cloak. The dragon started to shrink until it was in a 11ft tall biped shape, dragons on this world can shift between a giant beast form and a smaller biped form, not unlike a transformer or a Jinchūriki (人柱力, Power of Human Sacrifice) in full control of his Bijū(尾獣, Tailed Beasts).

The anthro dragon was female, now evident by her figure, and was kneeling before Kazuki. She kept her green scales and yellow eyes, now she had a very athletic physique that didn't detract from her feminine figure that showed her wide child-bearing hips and big E-cup breasts, proportional to her height, her muzzle was shorter but the head kept more or less the same shape, her hands with three fingers and a thumb, her legs were saurian in shape with three claw on the front on one on the back and on her back was her two wings still in the same place but smaller to match her new proportions.

“My name is Achuak Anhew, my life and hoard are now yours to do what you will,” said the dragon as she acknowledged her new master.

“A fitting name, 'Green Jewel’. It matches the color of your scales, so I going to call you Jewel from now on. Any objections?” asked Kazuki.

“None,” said Jewel after recovered from the shock of learning that her master knows draconic, not many outside of dragonkind know the language and to her it only showed that her master was powerful, knowledgeable and most of all worthy of her loyalty. A dragon will refuse to obey a weak master because they respect above all strength, but to them, strength came in many forms and so long it was acknowledged by a dragon you will have its respect.

“Good. I’m Ōtsutsuki Kazuki, ‘Ōtsutsuki’(大筒木) being the name of my clan and meaning 'great bamboo tree’ and ‘Kazuki’(和樹) being my given name and meaning ‘harmonious or peaceful tree’. It's a pleasure to meet you,” said Kazuki.

“My grandfather told me stories of a Ōtsutsuki when I was a hatchling. He said he saw a white being that fought against both Royal Sisters in the same year the queen passed away. A feat only matched by the dark usurper in the north and the dreaded centaur invader as well as the chaos serpent here on Equestria many centuries later. Are you perhaps related to him?” asked Jewel as she tried to remember more of her grandfather's stories.

“No, I’m not related to him. The one that fought the sisters was me, but they were too soft to kill me, so they sealed me instead. I managed to free myself recently,” explained Kazuki.

Jewel was stunned before her was the oldest enemy of the Royal Sisters, the thought that he could easily kill her if he wanted only made him more impressive in her eyes.

“Thank you for accepting me. What now?” asked Jewel as she got up.

“You can remain in this cave if you wish. Later I will give you my mark, but for now, I have to get used to the forest,” said Kazuki as he turned around and put his traveling cloak back on before walking outside, but he added before leaving, “you can find me in the former Castle of the Two Sisters.”

After that Kazuki continued to explore the Everfree Forest, by the end of the day he established himself as the top of the food chain by intimidating every being that mistook him for prey, everyone on this forest that came across him acknowledged him as the apex predator.

So Kazuki returned to his castle by the time the sun was setting, Hon calmed down and was more accepting to the idea of not killing the sisters, it might take a while for her to forgive them. Then Kazuki went to the master bedroom to rest after he established this entire forest as his territory and making that known to almost every being living here.

Canterlot Castle

Celestia was looking at the moon that was recently raised, this was the first night without the silhouette of her sister on the moon.

“Are you alright sister?” asked Luna as she entered in Celestia’s chamber to wish her goodnight before assuming her role as the guardian of dreams after a thousand years, but saw her sister with a worried look.

“Yes Luna I’m fine, it’s just that I feel as if I missed something important, like something happened recently that will have consequences later,” said Celestia before she sighed.

“Maybe you are just stressed, you should get some rest,” suggested Luna.

“Maybe you are right. Goodnight sister,” said Celestia as she went to her bed.

“Goodnight sister,” said Luna as she went to her on room to later enter the dreamscape.

Author's Note

In this universe Kazuki was the first enemy to ever be sealed by the royal sisters and also the first one they fought against as rulers.

The Kazuki's chakra cloak is similar to a Jinchūriki Form Version 1 without tail(s) and ears.

Here is some additional information:
Ōtsutsuki clan and Chakra from the Narutoverse
Thaumaturgy and Magic from the Nasuverse.
Nen from the Hunterverse

Kazuki's Mangekyo Sharingan is like the eyes that Indra had.