As soon as Harada killed Enmu,the entire train derailed from it's track.

Due to which many passengers died,though some of them survived.

"Argh,looks like I broke my ribs" Harada thought as he regulated his breathing.

"Breath,focus on the breath" he thought.

After a few seconds....

"Such great effects!" Harada exclaimed in amazement.

The pain had slowly faded away,it was as if his ribs never broke and he felt more powerful than before.

"This body really gets stronger the more injured I get" He analysed.

"Shit!, I remember that there'll come an upper moon after a few seconds and kill rengoku" I thought as I put my focus on my surroundings.

There was currently no one.

He couldn't feel anyone's presence aside from Tanjiro,Rengoku,Zenitsu,Nezuko,and Inosuke.

Nezuko and Zenitsu were near the train, unconscious

But he knew that the demon will come any second so he stood on guard.

.............

I saw Rengoku helping Tanjiro use to his total concentration breathing to clot his blood around his abdominal wound.

Suddenly,

*Bam*

Suddenly,a human-like figure jumped from the top of the derailed train.

Dust restricted everyone's vision.

Then,we saw someone,

It was the upper moon demon,Akaza.

As a Demon, Akaza took the form of a muscular young man with skin so fair that appears bright green-tinged white, decorated by a pattern of thick blue lines, which resemble the criminal tattoos he had as a human. The lines on his face curved through each of his eyes from below his ears to over his temples, another blue line running from the center of his hairline to the bridge of his nose, with two more lines running around his neck, three others branching off the lower one to his torso.

Akaza had short, bright pink hair that fluffed out around his head, and inward-tilting yellow eyes with pink eyelashes and blue sclera that looked somewhat like cracked glass, the kanji for "Upper Rank Three" etched into their irises.

"I am the upper moon Three demon,Akaza,today,I am here to fight the Hashira!" He declared fearlessly.

Seeing him,everyone except Harada and Rengoku felt a chill down their spine.

"I don't know what to do,should I join the fight?...Nah,that just feels like courting death...then the only chance I'll get to kill Akaza is when Rengoku san sacrifices himself?" Harada was completly calm even when thinking about this.

The total concentration breathing and the enlightenment he got in the butterfly estate had made his mind strong enoigh for him to stay calm in dangerous situations like this.

After a few seconds,the fight started

We were told to stay away by Rengoku san.

..........

As they were fighting,Tanjiro couldn't see anything,yet Inosuke was able to see it.

"Even if I can see what's happening,I can't find an opening or angle from which I can jump in the fight,even if I could,then I'd probably just be a hindrance to Rengoku san" Inosuke thought.

Currently,Harada was suprised to see know that he was able to clearly see how they were fighting,not a single detail,not a single strike could escape Harada's vision.

"It turns out that I'm able to clearly observe,but I'll still wait for the right moment" he thought.

The fight continued for a what felt like a few hours.

Rengoku attacked Akaza with full force.

Akaza ambushed him from below, complimenting his exceptional movements.

Rengoku immediately dodged his attack and cut off his arm, but Akaza retaliated by using his legs to launch him outside the forest.

Then Akaza suddenly dashed forwards and punched Kyojuro's guts, which caused it to bleed. Kyojuro coughed out saliva and vomit but remained steadfast and performed the Flame Breathing: Second Form - Rising Scorching Sun. Akaza dodged his technique and attempted to attack Kyojuro while he barely managed to parry all his blows with his katana.

"Rengoku,become a demon,you'll get tens of times stronger the moment you become a demon!" While preparing to attack Kyojuro with a stronger attack, Akaza continued to convince him to become a demon, saying that his strength and power would be able to grow exponentially.

"No,I refuse!" Rengoku said as he prepared to use his final attack.

"Flame Breathing: Esoteric Art - Ninth Form ー Rengoku" He said as it started feeling as if he was engulfed in flames.

He then used his full power to kill the demon in one blow,he watched with eyes full of admiration.

As expected Rengoku's sword strike nearly cut Akaza in two halves but at the crucial moment,Akaza contorted his abdominal muscles and stopped the blade from cutting him completly as he prepared himself to counter attack.

"That's the moment" Harada thought as he moved his body and in a blink of an eye he appeared behind Akaza and....

He used his blade to cut both of Akaza's arms.

*shii* *shii*

Akaza's full attention was on Rengoku's swrod strike so he left an opening and that as his biggest mistake.

Harada successfully cut both of Akaza's arms as it shocked Akaza.

This gave Rengoku a chace to use his full power once again as he pushed his nichirin blade and cut Akaza in two halves.

"H-how can you do this?!....Attacking your enemy from behind,this is not what a demon slayer is supposed to do!!" Akaza's screamed as his upper body fell on the ground and he started turning into dust.

"Who said that?" Harada said with a cold expressing ss he used his blade to stab Akaza's head as he added "Akaza,you were a human once,yet you have become a demon...I wish to god that he gives a better life in your next reincarnation" he said in a gentle tone.

Akaza went silent for a while then asked "What is your name?"

"Kamado Harada" he replied

"What's yours?" he asked

"My n-name is A....Hakuji Soyama" he didn't give much of a response,instead,his eyes were filled with tears!

Harada remembered that Akaza had a very bad life when he was a human.

This caused him to feel as if blades were stabbing his heart,begging to him to cry for Akaza.

But he held his tears.

After a few breaths of time....his body completly turned into ash.

After that,he heard a sound of someone collapsing beside him.

It was Rengoku,the fire pillar.

"This time,I've saved Rengoku san's life,now the battle in the infinity mansion should be a bit eaiser" Harada thought as he felt as if his legs had become noodles.

After that,he too,fell unconscious.

Harada had used all of his power to make that quick movement to cut Akaza's arms.

No matter how strong he was currently,he still had his limits.

..............

After a few hours,

In a big mansion,

There was a black haired youth,around 18-19 years old.

At the moment he was unconscious.

He had helped a Hashira in killing an upper moon.

In another room,

Tanjiro,Zenitsu,Inosuke were recuperating as well.

Rengoku was currently in another room since his injuries were fatal,he now would have to retire as a demon slayer.

To be continued......