3rd POV. Kagaya's Quarters, Ubuyashiki Estate.

Ubuyashiki Kagaya, the 97th Leader of the Demon Slayer Corps, and the current Head of the Ubuyashiki Family.

Unlike Muzan who holds his demons with fear.......

Kagaya leads the Corps with respect. Even though in the past, he was subjected to slander. An example of this is when Shinazugawa Sanemi, before he became the Wind Pillar, he was angry at Kagaya because of Masachika's death.

But Kagaya took the criticism gracefully, even apologizing to Sanemi. Apologizing to Sanemi that Kagaya also wanted to lay his own body and life to protect innocent people, but whenever he even perform a single swing of a sword, it drains his strength almost immediately.

Not to mention, the Hashiras during that time, Giyu, Gyomei, Kanae, and Tengen, told Sanemi that Kagaya memorized the names of every Demon Slayers and even their background when he became the leader. The fact that Kagaya even read Masachika's will.......this is how the Wind Pillar gained his utmost respect for the Master.

In some cases, there are individuals who could tell right away that Kagaya is a respected person, even just from the first glance alone. The first who achieved this feat is none other than Uchiha Sasuke.

Ever since Sasuke joined the Corps, even without his Sharingan, he knew that Kagaya's heart is filled with respect and humility to everyone. Which in turn, he gained respect of the Hashiras.

But what surprised Sasuke even more is that he knew the history of the Uchiha Clan: their ancestry beginning from Amaterasu to Indra, the founding of the Uchiha Clan, the background of the Uchiha Clan's two forbidden genjutsus (Izanagi and Izanami), Uchiha Madara and the Eternal Mangekyo Sharingan.

Sasuke wasn't really able to learn the Uchiha Clan's history because his father died when both he and his younger brother were still young.

So, Sasuke learned of the Uchiha Clan's long history, history that was filled with conflict and especially, hatred. Yet times change, and the fact that the Uchiha Clan's pacifist nature still somewhat prevailed, Sasuke never denied the dark history of his clan, in fact, he took it as a lesson to never let the Curse of Hatred destroy everything again.

Knowing the risks of joining the Corps, Sasuke decided to write his journal, his life with his family, his recollections, the demons he encountered, the friends that he made in the Corps, Naruto and Shisui, and his message for his younger brother, Sora, in any case that Sasuke will meet his end.

He also wrote upon the journal on how the Sharingan is activated by extreme emotions such as hatred, grief, and love.

As for losing a loved one, the manifestations of the Mangekyo Sharingan, their diversity to each Uchiha, in terms of pattern and even abilities. In fact, Sasuke believed that if Sora ever awakens his Mangekyo Sharingan, his younger brother might also possess the Amaterasu, the Visual Prowess of Sasuke's Mnagekyo Sharingan.

His reason is because they are brothers.

Once Sasuke concluded his journal, he gave it to Kagaya for safekeeping, and in the right time, to hand it over to Sora. The Master kept his promise that if something ever happens to Sasuke, he'll take care of Sora.

Kagaya knew at that moment that Sasuke is about to die in the hands of Muzan. Sasuke sensed that Kagaya foresaw his death, and Sasuke never even questioned it, in fact, he told Kagaya......

"My mother knew that death is on her doorstep, yet she never fret, because as long as she can still spend time with her children, she doesn't care about dying. The same goes for me."

"As long as I can protect Sora, even if it kills me, then as long as I keep him safe......I will gladly face death head on."

But before Sasuke left he left one final message for Kagaya.

"For the time being, I entrust my eyes to be under your protection. I know my work isn't supposed to be finished yet, but I trust my brother, to conclude my work."

Kagaya knew what Sasuke meant, if Sasuke still has the ounce of strength left after he battled Muzan, he will entrust that his Mangekyo Sharingan to be safe within Kagaya's protection.

And it happened. Sora followed his brother's last instructions. Kept Sasuke's eyes into special containers, entrust a Demon Slayer to bring it to Ubuyashiki Kagaya, and in the future, for Sora to inherit his brother's eyes when the time is right.

As Kagaya contemplates inside his quarters......

Kagaya: .........

Kagaya: *sigh*

Kagaya: Sasuke.........

Kagaya: I'm sure, your brother will finish your work.

Kagaya: You can rest easy. Someday, I'll join you over there. But not until I fulfill my promise to you.

Kagaya: I won't die, not until your brother gains the Eternal Mangekyo Sharingan.

Kagaya: That's what I promised.

A few more days passed.......

Sora who clearly improved his overall abilities, with improvised training, he is now ready to rejoin Tanjiro and continue their journey.

Not long afterwards, Sora was called by Kagaya.

Sora: You called for me, Oyakata-sama.

Kagaya: I heard from Amane that you also conducted your own training.

Sora: I have to improve. In order for me to protect Tanjiro and Nezuko in even greater dangers.

Sora: I just don't want to be knocked every after battle.

Sora: I can't have that.

Kagaya: Your dedication to protect them, reminds me of a certain someone.

Sora: Really?

Kagaya: Yes. You two are the same.

Sora: So, Oyakata-sama, I had a feeling that you called me here, is it because I'll be joining Tanjiro on his missions?

Kagaya: Correct.

Kagaya: Tanjiro and his friends are sent to the Infinity Train and to meet with one of the Hashiras over there.

Sora: May I know the name of this Hashira?

Kagaya: His name is Rengoku Kyojuro, the Flame Hashira.

Sora: Flame Hashira......

Sora: Hmmmm, wait, does it mean he's using a breathing style known as "Flame Breathing" or some sorts.

Kagaya: The Hashiras are named after their own breathing styles.

Sora: It seems my intuition hit the mark.

Sora: Maybe I can ask this Flame Hashira guy if he knows about the Hinokami Kagura, since it is related to fire.

Kagaya: You are to meet with Tanjiro at a designated train station.

Kagaya: The crow will guide you there.

Sora: I see.

Sora: Then, I'll have to pack my things and head off.

Sora: Also, thank you for letting me stay here, Oyakata-sama.

Kagaya: I should also be the one thanking you. For the days that you've been here, you entertained my children and helped them in their duties.

Sora: Ah, haha. I guess. Tell your children that I'll bring them some souvenirs once I got back.

Sora left the quarters as Kagaya smiled.

Kagaya: You brothers really are the same.

Kagaya: Sasuke and Sora.

Sora packs his things. He also received his own Nichirin Sword, and it turned to black.

Amane herself was surprised that she will see a black Nichirin Sword with her own two eyes.

She knew the stories surrounding the Demon Slayers who possessed the black nichirin blades, such as dying out even before discovering their own potential.

When Amane relayed this information to her husband, he just smiled, knowing that Sora will be alright.

Sora was also offered to wear the Demon Slayer's uniform but he refused.

With everything ready, Sora sets off to his mission after he bids farewell to Amane and to her children.

With the crow's guidance, Sora finally reached his destination, the train station. While on the way, Sora asked the crow about the mission and the crow told him about the missing passengers of the Infinity Train.

The fact that the Demon Slayers who were sent to investigate the missing passengers, never came back.....this alarmed the Corps.

So by sending a Hashira, they hope they can solve the mystery.

Not to mention.....

Sora: Trains, huh. Come to think of it, I've also used to work at a train station.

Sora: I guess my knowledge regarding this matter could be useful......or maybe not. I only used to like maintain a train's engine and the fuel sources.

Sora: Come to think of it, somehow, I chose that job because I was adopted in a family of coal burners.......

Sora: Yeah......but somehow, I felt like I had another reason. A high paying job, I guess. But whenever I remember my past job......

Sora: I felt like I knew SOMEONE who also used to work in a train station......

Sora: Ah, nevermind. I'll think about it later. I got to catch up with Tanjiro and the others.

Sora decided to ask the crow for more information about the said mission.

Kasugai Crow: In fact, the Infinity Train is about to go back into service today.

Sora: Back on service today? Did they do some maintenance work on it?

Kasugai Crow: Who knows.

Sora: Well, if a train is out of commission, it's either they will fix something on the train like the engine, the cars, the wheels, or any parts of the train that needs maintenance.

Kasugai Crow: You sure know a lot.

Sora: I used to work with maintaining the train and stuff.

Sora: So, I guess putting me on this mission is kinda helpful.

Sora: Or maybe not. Because according to the information that you gave me.....

Sora: Over 40 people went missing.....

Sora: A murder case, so it seems. But the fact that Demon Slayers were sent there.....

Sora: A demon is behind the incident.

Sora: And not to mention, the Infinity Train.......

Sora: That is actually the train that I used to work on.

Kasugai Crow: What?

Sora: Let's say.......the Infinity Train is the pride and joy of the company that I used to work for.

Sora: Did the company regained back their lost fortune and even won the case?

Kasugai Crow: What are you talking about?

Sora: Back when I was still working at the company that handled the Infinity Train.....

Sora: The train got a malfunctioned engine that exploded and killed a conductor.

Sora: The said explosion caused the train to crash and injured a lost of passengers.

Sora: Because of that accident, our company was blamed, especially the lead engineer.

Sora: I mean, we know that the train wouldn't got a malfunction during that time.

Sora: Our company practiced a strict rule that went like on something like this.

Sora: "If there is just a single fault in the train, no matter what, we'll suspend the operation and put the train back in maintenance."

Sora: The chief believed that even a small malfunction can cause the biggest accidents.

Sora: But the fact that a very major malfunction occurred during that time......

Sora: We never overlooked anything. We even gave the go signal to board the train.

Sora: And the fact that we never even got to investigate the cause itself.....

Sora: *sigh*

Sora: I just hope that the chief is alright.

Sora: Or if there is a new company that handled the Infinity Train, I hope they won't make the same mistake ever again.

Sora got into the train station at three hours before sunset. Once he got the ticket and boarded the train, he went and explored the interior of the train.

Sora: Woah, so they improved the interior, huh.

Sora: It seems like this train went through a lot of renovations.

Sora decided to wait for a while and settled down for a seat.

Sora: Hmmm, the crow told me before I boarded the train.....that I'll meet Tanjiro, Zenitsu, and Inosuke.

Sora: Maybe they were also assigned to this mission.

Since it's still going to be a while before the train departs, Sora decided to get a bunch of newspapers to read in order to pass the time.

And hopefully to gather some information about the recent events surrounding the Infinity Train.

As hours went by, the train was filled with passengers and Sora went and observe to see if there is something strange.

Sora: Alright, nothing strange as of the moment.

While he is busy reading newspapers, he knew it is still going to take a while for the train to move out.

When he saw a vendor, he asked if the said vendor is selling tea to which the vendor replied.

Vendor: Of course.

Sora: Then, how much is it?

Vendor: 6 sen. Oh, would you like to buy some bento as well?

Sora: How much?

Vendor: 36 sen.

Sora: Since I've only eaten rice balls when I was on my way here.

Sora: Alright.

After paying and receiving the items that he paid for, the Uchiha decided to eat for a while.

Sora: Itadakimasu.

As he is eating, a man with bright yellow hair with red tips, wearing a flame patterned haori approached his seat.

The Uchiha saw him as he stopped eating.

Sora: Hm?

???: This the other seat taken?

Sora: *slowly swallows the food*

Sora: Uh, no.

???: Then, would you allow me take the seat beside infront of you?

Sora: Sure. I don't really mind?

???: Thank you!

Sora: Mm.

Sora noticed that the man is wearing a Demon Slayer uniform, but he went quiet for now as he doesn't want to be suspicious to the newcomer.

However, the one that caught his attention is the two stacks of bento that he is carrying along with him.

Sora: Woah.......did he bought all of those? How much money does this guy have anyway?

Sora: Man, sure it is nice to be rich, huh.

The yellow haired man went to grab a bento, opened it, and he also went to eat.

???: Umai!

Sora: .......

???: Umai!

Sora: ..........

???: Umai! Umai! Umai!

Sora: Uh......weird.......

The Uchiha just didn't mind the attitude of the one sitting in front of him.

Sora: I know the food is good but please.......

Sora: He can just savor the flavor without being that loud.

Sora: But knowing that this guy is a demon slayer......

Sora: Also, the train is about to depart. Tanjiro and the others haven't even arrived?

Sora: Or maybe they are in the much further cars.....

Sora: Also, I feel like the guy in front of me is somehow strong.....I mean, just by looking at him, past his attitude.

Sora: Um, what is your name?

Kyojuro: My name is Rengoku Kyojuro!

Sora: Oh, nice to meet you, Rengoku-san.

Sora: My name is Sora.

Kyojuro: Nice to meet you, too, Sora!