Jörmungandr

Ryujin Jakka seemed happy with his name if the pulse of warmth the sword sent up my arm was any indication. 

It had been one of my favourite zanpakuto in Bleach. A sword that was capable of turning whole cities to ash and carving mountains in half with a glancing blow with just the tip. It was hilariously overpowered in the series and I knew that I could pretty much do the same thing. 

My raven returned a few days later and sent me a telepathic message about a mission. Currently I was the lowest rank in the slayer corps but I knew I would shoot my way to the top. 

I had done my research into the corps while I was waiting for missions. It wasn't unlike being a shinobi back in Konoha. Only the enemies were vampire like demons instead of other ninjas. 

I put on my dark blue haori with the Uchiha fan on the back and tucked Ryujin Jakka into my belt sash. Stepping out of my house I closed the door before disappearing in a shunshin. 

It didn't take long for me to reach the designated location where the demon had been sighted. The village I was in was empty, my senses telling me that there were no living beings in the area. 

I crossed my arms and waited for the demon I felt lurking in a shadow to make its move. My cloak fluttering in the wind, I felt like a villain almost. Activating my Sharingan I sneered at a wavering shadow that was sneaking towards me. 

"So you've finally come out." I drawled. 

"Foolish human, I will feast on your flesh!" The demon growled as it emerged from the darkness. 

"Show me how you dance." I replied without uncrossing my arms. 

The demon roared and charged at me.

[Scene Break]

"Oyakata-sama, here are the monthly reports from the Hashira. I had them include observations on the latest batch of Demon Slayers as well." 

"Thank you Amane, I have heard from Kiriya and Hinaki that there are a few promising individuals in this group." 

"Hai, they mentioned watching Akimitsu Uchiha defeating many demons without even using a weapon." 

Kaguya Ubuyashiki would have raised an eyebrow if he could, knowing his wife and his daughters though he knew that they wouldn't joke about something like this. 

Instead of replying he dove into the reports from the Hashira. Most of the reports were standard and nothing really popped out at him. At least that was the case until he reached Giyu's report. 

He had already gotten word from Giyu about a young boy the Water Pillar had saved. Giyu was in charge of protecting a large area like all the other Hashira. Unlike the other Hashira however, Giyu was also the ranking Slayer to Akimitsu Uchiha, who was reported to have built a small hut near the mountain the boy Giyu had saved used to live on. 

In his report Giyu mentioned that Akimitsu had single-handedly killed nearly a hundred demons in the month that he had been in the Demon Slayer Corps. 

Giyu also brought up the fact that Akimitsu's nichirin blade was the colour of hot steel and emitted scorching flames. 

In the reports Giyu noted that Akimitsu more often than not, left very little of the demons he killed. The demons were burned to ashes with whatever breathing style Akimitsu used. 

Nearly the entire report was about how Akimitsu went out of his way to eliminate as many demons as he could. Giyu only spoke to the new slayer once and he mentioned that Akimitsu had the aura and strength of a Hashira. 

Ubuyashiki was deep in thought, the Demon Slayer Corps was always short of man power. The Hashira were stretched thin as is. 

With Giyu's report he knew that he had to meet this Akimitsu Uchiha individual in person to gauge their character. If all things went well, the Corps would be gaining a new Hashira very soon.

[Scene Break]

It has now been a month since I joined the demon slayers in this world. I rode through the ranks relatively fast and made a name for myself. My raven relayed all this information to me straight from HQ. 

I had to give it to the slayers for being extraordinarily cautious enough to not give the location of their main base away even to their warriors. 

Not even the Hashira, basically generals, knew where the main HQ was. That took dedication from whoever this Oyakata person was. 

"Raaaaahhh! Filthy human scum." The latest demon about to be added to my kill count screeched. 

I had killed dozens of the damn things but they just seemed to spawn out of the ground. According to the other slayers I had spoken with, demons could be created by ingesting the blood of a demon. It just made them sound even more like vampires rather than demons. 

I dodged clumsy haymakers and clawed slashes. Not bothering to draw Ryujin Jakka just yet I continued to toy with the demon. 

"This bores me, begone." I finally spoke. 

The demon sputtered, before rushing at me. I slowly drew Ryujin Jakka making the air around me spike in temperature. 

"All things in the universe, turn to ash… Ryujin Jakka."

Around me an inferno of blazing heat scorched the earth black. The demon didn't even have time to scream before it was vaporised with a single swing of my sword. The ground started to turn into magma just as I sheathed Ryujin Jakka. 

Once the blade was back in its sheath the air quickly returned to its normal temperature. Brushing the dust off of my clothes I turned to the treeline where I sensed an observer. 

"Giyu-chan, you can come out now. The scary demon has been dealt with." 

Giyu Tomioka stepped out from behind a tree, beads of sweat on his forehead. He looked as stone faced as he usually did. 

"Uchiha-san, Oyakata-sama requests to meet with you personally." 

I enjoyed teasing the Water Hashira so I gave him a lopsided grin. 

"Hey don't ignore me Giyu-chan… I know that big scary demon made you quake in fear." 

The Water Pillar remained expressionless. 

Sighing, "Fine, let's go, you kill joy." 

"Report to the temporary headquarters with haste, do not make Oyakata-sama wait." 

The stone faced Hashira said before walking off. I shook my head and summoned a raven. Watching it fly off I began to follow it towards the temporary headquarters that Demon Slayer Corps had set up as a meeting place and a decoy. 

''What a spoil sport.'' I muttered at the thought of Giyu and his ever present dead fish face. 

Chaining a few shunshins I quickly followed after my summon. An hour later I was at the gate of a large mansion guarded by two Demon Slayers who immediately took notice of my arrival. 

"Akimitsu-san, Oyakata-sama is waiting inside."

They let me in without any issues. Personally I think that they were slightly afraid of me. I did keep my Sharingan constantly activated for the last month and the stories of my exploits have spread. 

They had started calling me Hinokami, which I figured roughly translated to fire god. In a sense Ryujin Jakka combined with my liberal use of Gouka Mekkyaku did leave a certain impression. 

In my mind every time I saw someone using their 'breathing style', which was what they called their kenjutsu for some reason, the slayers seemed to be imagining elemental effects. 

Chief among them was Kyojuro Rengoku. The current Flame Hashira who I had met a week ago by chance, all of his 'breathing forms' names were fire themed. As effective as they were, I couldn't help but to compare them to chuunibyou fights.

That said, Kyojuro was my self proclaimed rival due to my actual abilities in using fire based attacks. He swore that he would one day learn how I was able to use fire like I did. 

I was almost tempted to break immersion so I could give him chakra and watch the chaos unfold with the eccentric teen flinging actual flames at demons. 

'Maybe before I leave this world.' I hummed in my head as I waited by the doors to the main building. 

The doors slid open and I was greeted by a white haired woman with similar eyes to the creepy twin girls from the mountain. 

"Uchiha-san, please come in. Oyakata-sama is waiting." She said in a monotone voice. 

"Hn." I continued with my Uchiha attitude. 

Inside the room seated on his knees in front of a Japanese style table. There were already two steaming cups of tea across from each other on the table top. 

The man had some nasty scarring across his face, mostly covering his eyes possible causing him to be blind. I took Ryujin Jakka out of my sash and set it next to me as I sat cross legged on the opposite side of the scarred man. 

The man had a serene smile on his face as he addressed me. 

"Akimitsu Uchiha-san, I have heard many great things about you from Tomioka-san. He tells me that you've killed countless demons in his sector making his job easier." 

"Hn, the demons are surprisingly weak." 

The man chuckled lightly, "Perhaps you are too strong." 

"Perhaps"." I replied. 

"Please, tell me about yourself Uchiha-san, why did you join the Demon Slayer Corps." 

I crossed my arms and pretended to think for a moment. 

"I would be lying if I gave some self sacrificial answer, to be perfectly honest I joined so that I could test the might of these demons, thus far I have been rather disappointed." 

The man pondered my words, "Are you familiar with the Upper Moon ranked demons?" 

"No, but from your tone I assume these are the most powerful demons?" I asked

"Indeed, Mazan Kibutsuji is the progenitor of the demon race. Serving under him are the Upper Moons and serving under them are the Lower Moons,

"the ultimate goal of the Demon Slayer Corps is to find Kibutsuji Muzan and to kill him so that we may bring an end to the demonic scourge that has plagued our world." The scarred man continued.

"A lofty goal, from what it sounds like, Muzan has escaped countless times and eluded the Corps." I hummed in response. 

"The Corps came close centuries ago. A man named Yoriichi Tsugikuni nearly killed Muzan but the progenitor escaped through a secret method." 

"Must have been unbelievably strong, to have nearly killed Muzan." 

"Indeed he was, Yoriichi was rumoured to be the founder of the first breathing style. A style lost through the ages." 

"While I enjoy history as much as the next man, I believe you had a point in bringing me here?" I asked the man, trying not to sound impatient but also conveying a sense of impatience. 

"You are correct Uchiha-san. I believe that you are a piece of a puzzle that will help in our quest to defeat Muzan. I have brought you here to discuss your future in the Corps." 

"Hn, you seek to elevate me?" 

"Yes, you clearly have the strength beyond that of any of the Hashira under my command. It would be a waste of talent to keep you in your current rank." 

"I was led to believe that there is only a set amount of Hashira. Wouldn't elevating me to a Hashira throw off this balance?" 

"Currently there are only nine Hashira, we are missing the tenth." 

"Fine, I accept." 

"Excellent, but I have to ask… what is your breathing style?" 

I paused for a moment, I didn't really have a breathing style. Ryujin Jakka negated the need for a breathing style. I did copy that swordsman's style with my Sharingan though so technically I did have a style I could potentially use.

The original Ryujin Jakka was said to be even hotter than the sun. I guess I can go with that. 

"It has no name, but if I were to give it one, I'd call it; The Breath of the Sun." 

[Scene Break]

I sat on the porch of my newly assigned home. Kaguya Ubuyashiki had formalised my promotion the day after our meeting. He had also assigned me a new home closer to the temporary HQ. 

People were shocked at the announcement of a new Pillar; The Sun Hashira. Though when they heard it was me, they immediately figured that I had earned the title by killing so many demons in such a short amount of time. 

I was due to meet the other Hashira today, a monthly meeting of sorts to discuss and compare plans and information. 

Ubuyashiki had wanted to assign subordinates for me but I insisted on finding my own. I had my eyes set on the siblings. It was only right that I taught the kid how to actually use the fighting style his family had learned from Yoriichi. 

I had deduced that the 'mysterious swordsman' was actually Yoriichi after comparing the few records that the Demon Slayer Corps had of past members. 

I had also heard from Giyu that Tanjiro, the boy he had saved, was starting to train to become a demon slayer. 

He would be joining the selections in a few months. Giyu didn't bring up Tanjiro's sister though, I figured that he was hiding this information from the other Hashira so that they didn't kill her. 

My raven croaked out a message letting me know that everyone had arrived for the meeting. I put Ryujin Jakka in my sash and Hiraishin'ed to the meeting place. 

People were startled by the flash of lighting and my sudden appearance. A young man with white hair and numerous scars leapt at me with his sword drawn. 

I merely turned an uninterested eye at him, Sharingan spinning. The young man froze mid air as I caught him in my Tsukuyomi. I didn't torture him though, instead I had to to where he was being chased by immortal furries for three days straight… I guess I tortured him a little. 

The other Hashira who were about to jump in to stop him skidded to a halt when he crashed into the ground before jumping up and letting out a girlish scream. 

"Kyaaa! Keep them away from me!" The white haired Hashira screamed. 

Everyone stared. 

"Pffffft." A big breasted girl began to snicker. 

The white haired young man glared at her making her break out into giggles. 

"Sanemi-kun what's wrong?" She asked between her giggles. 

'I think she has Gabriel beat on having massive knockers.' 

"S-shut up! You!" He glared at me, "what did you do to me?!" 

"I didn't do anything." I smirked.

Sanemi grit his teeth and picked up his sword, just as he was about to attack me again a flame haired young man stopped him. 

"Comrades should not fight Sanemi-san." 

"Get out of my way Kyojuro." 

"Oyakata-sama has arrived, please compose yourselves." A soft voice reached my ears. 

"Tsk… fine." Sanemi scoffed before stimming off back to his position. 

"Thank you, Kocho-san." Kaguya said in his calm tone. 

I looked at the girl that had broken up the fight, she had a butterfly themed Haori and a gentle air about her. I guessed that this was Shinobu Kocho, the one in charge of the Butterfly Mansion. 

The Butterfly Mansion was basically the hospital to the Demon Slayer Corps. There everyone from the lowest ranking cannon fodder to the Hashira, went for treatment and training. 

Kaguya Ubuyashiki began the meeting and introduced me to everyone there. Kyojuro already knew me so the flame haired youth had a big goofy smile on his face. I had a feeling he was going to challenge me to a spar later. 

"Uchiha-san is the newly appointed Hashira, I have given him control over the Tsugikuni sector. Uchiha-san, please introduce yourself." 

"Hn…" 

"…" Everyone stared with deadpan expressions. 

"Very well, my name is Uchiha Akimitsu, I like women, fighting, and music. I hate demons and people who monologue, my dream is to have a family with lots of kids." 

I gave the standard Naruto introduction. Kyojuro had a big smile on his face, another Hashira that looked like a ninja nodded approvingly at my 'I like women' bit, Sanemi glared at me while everyone else had unreadable expressions. 

Ubuyashiki sighed before turning towards the others and speaking. 

"I suppose that's as much as we will be getting, everyone else please introduce yourselves." 

"Hai Oyakata-sama!" They all responded. 

[Scene Break]

After everyone went around to introduce themselves I barely paid attention to the reports. Giyu brought up Tanjiro and how the young boy would soon face his selection trail. 

Other than that nothing really stood out to me. Using my Sharingan I analyzed everyone's survival chances by going through simulations in my head. 

Unsurprisingly only a few of them had the chance of actually surviving an encounter with Muzan. I based his power level on the multiple demons I had killed multiplied by what I assumed was the peak of this world. 

However 'plot armor' wasn't a thing in this world, everyone could potentially die. While I wanted to experience this world as immersively as possible, I also didn't want people to needlessly die. 

As I was about to leave once Kaguya closed the meeting I was stopped by Kyojuro and Shinobu, the Insect Hashira. 

"Uchiha-san, please wait. Kocho-san wishes to ask you a few things." Kyojuro said. 

Raising an eyebrow I looked at the smiling Insect Pillar.

"And she couldn't come to me herself?" 

"Ara ara, you have such an imposing aura." Shinobu said with a gentle smile. 

'She really did the thing…' 

"I apologise…" I deactivated my Sharingan, shocking the two of them when I revealed my normal eyes, "I am not used to being around many people." 

I gave a totally bullshit reason for my Emochiha impression but I felt like it was within character at the moment. 

"I see, I had no idea your eyes could change colours Uchiha-san." Shinobu replied. 

"Neither did I." Kyojuro added. 

"It's a special ability of my… clan." I answered. 

"My questions are related to your eyes and the strange abilities you possess, would you mind answering them Uchiha-san?" Shinobu asked. 

"Hn… I will do my best." 

Shinobu smiled, "Good, let us meet at the Butterfly Mansion tomorrow afternoon. It is not far from here." 

I nodded and turned to leave but Kyojuro stopped me once again. 

"Uchiha-san, please… humour me with a spar." He gave me a small bow. 

I contemplated for a moment. "I have the time… why not." 

The other Hashira stopped whatever they were doing and glanced our way after having heard me agree to a spar with Kyojuro. 

'He must be one of the stronger ones then… I wouldn't be surprised if this duel made a few more of them challenge me. Oh well, it's only mid day, I can beat on a few people for a bit.'