They won the Holy Grail War, but this turned out to be the Virtual Tree Universe.

Chapter 14 Learning Breathing Techniques (Please continue reading)
Dan Lei's flames, which completely annihilated the demon, truly impressed Urokodaki Sakonji.

Given the industrial capabilities of the Taisho era, how could the Demon Slayer Corps possibly create flames of 2000 degrees Celsius? Even if they could create flames of 1000 degrees Celsius, it would be a struggle.

In the anime, the flames wrapped around the sword of Flame Hashira Kyojuro Rengoku could not ignite the Crimson Blade, proving that his flames were insufficient to make the Nichirin Blade's metal glow red.

The original work describes a method to generate that instantaneous high temperature by having the Nichirin swords collide with each other. In other words, the temperature at which the Nichirin swords turn red is not too high, otherwise this method would definitely not be able to reach the required temperature.

Although it is unknown what temperature the metal material of a Nichirin sword needs to turn red, considering that ordinary metals need 500 to 800 degrees to reach a "red-hot" state, the temperature for forging a Nichirin sword could not have exceeded 1000 degrees by much. Otherwise, given the technology of that period, how could ordinary craftsmen have mass-produced so many Nichirin swords?

The Demon Slayer Corps definitely did burn demons to death, but they certainly didn't actually kill them.

Therefore, it was completely unimaginable for Urokodaki Sakonji that Dan Lei could burn the demon to death with a flame of 2500 degrees Celsius; he directly regarded it as divine fire.

As for Sasaki Kojiro, Urokodaki Sakonji had no idea when he was standing there, and even though he was right in front of him, he still couldn't sense his presence. He naturally agreed that this was the legendary state of oneness with heaven and man.

Seeing that Urokodaki Sakonji had already submitted, Dan Lei naturally adopted a friendly attitude, returning the greeting and saying...

"Mr. Urokodaki Sakonji, I have long admired you."

I presume Mr. Yoshiyuki Tomioka has already explained the situation to you. We'll be in a bit of trouble from now on."

Upon discovering that Dan Lei was not putting on airs at all, Urokodaki Sakonji naturally didn't act as aloof as he had when he first met Tanjiro. He immediately expressed that it was a good thing that Dan Lei was willing to study demons, and that providing a place was what he should do.

While Tanjiro and Urokodaki Sakonji were exchanging pleasantries, Tanjiro and Nezuko had already buried the dead in the temple.

Nezuko is very strong, and there are everyday tools like shovels in the temple's backyard, so they are very fast.

After burying the body, Tanjiro did his usual prayers and then went to find Danlei, only to find Danlei talking to someone wearing a tengu mask.

Seeing that Tanjiro had already buried the body, Dan Lei naturally introduced it to Urokodaki Sakonji.
“Mr. Urokodaki Sakonji, this young man is Tanjiro, and the one behind him is Nezuko. I can testify that she hasn’t lost her temper even once these past few days.”

However, after hearing Tanjiro's words, Urokodaki Sakonji did not immediately express his opinion, but instead slowly walked up to Tanjiro and said...

"I am Sakonji Urokodaki, Tanjiro. I ask you, what would you do if your sister ate someone?"

Tanjiro was naturally taken aback by this question. He simply could not accept that his sister ate people, because he knew that eating people was evil, but he couldn't bear to hurt his sister.

However, this moment of hesitation immediately earned him a slap from Urokodaki Sakonji, followed by a reprimand.

"Unqualified! The judgment was too slow! Hesitation is written all over your body! Your determination is not firm at all!"

After your sister eats people, you only have two things to do: kill your sister! Then commit suicide! That's what it's like to have a sister who has become a ghost.

So remember, never let this happen, never let your sister take the life of an innocent person!

Tanjiro was completely stunned by the beating, so he couldn't help but look at Danlei, who had become somewhat of a support to him in the past two days.

However, Dan Lei also spoke sternly at this moment.

"Tanjiro, don't look at me."

Mr. Urokodaki Sakonji is right. If your sister is a cannibal, the best thing you should do is kill her before that happens.

If you can't do it, I will. If I'm no longer with Nezuko by then, I'll rush back and kill her as soon as I find out.

Then, I will leave myself with a scar that will never fade, and remember this for the rest of my life.

Also, don't rely on me for everything. I'm just a passerby in your life, and I'll leave sooner or later. You need to learn to be independent. Otherwise, after I'm gone, are you going to ask Nezuko, who's already struggling to express herself clearly, for help when you run into problems?"

Tanjiro's eyes cleared immediately after being scolded by Danlei, and he stood up straight and answered seriously.
"Yes, I understand!"

Seeing that Tanjiro understood his meaning, Urokodaki Sakonji continued to speak to Tanjiro.

"Giyu Tomioka has already told me about you and recommended that you join the Demon Slayer Corps."

So, I'll follow the procedure and test whether you can become a demon-slaying swordsman.

"Get your sister into the box, carry her on your back, and follow me."

After saying that, Urokodaki Sakonji also spoke to Dan Lei.

"Lord Danlei and Lord Sasaki Kojiro, please follow me."

After saying that, Urokodaki Sakonji started jogging along the country road.

Urokodaki Sakonji was clearly testing Tanjiro here, so he wasn't running very fast. With the physical abilities of the Danlei Chiming Dragon Clan, he could easily keep up. As for Sasaki Kojiro, he immediately thought it was too slow and turned into a spirit.

As for Tanjiro, he would need to run at full speed while carrying the box to catch up.

However, Tanjiro's physical strength is still up to par, as he is a charcoal seller who often needs to bring a lot of charcoal down the mountain to sell and return on the same day.

Moreover, whenever he feels like he can't go on, he thinks of Nezuko and encourages himself to keep going with love.

And so, from dawn to noon, and from noon to evening, with only a few meals and water breaks in between, Tanjiro persevered until he reached Urokodaki Sakonji's house.

In fact, if it were a regular Demon Slayer Corps swordsman selection, Tanjiro would have qualified long ago by now.

However, 13 of Urokodaki Sakonji's disciples have died in the final selection process since he became a trainer.

This led Urokodaki Sakonji to doubt his own teaching abilities and to become more stringent in selecting disciples, since sending out those who were not strong enough would be tantamount to sending them to their deaths.

Therefore, Sakonji Urokodaki will give Tanjiro a final test, requiring him to run alive from the mountain full of traps to the front of the house at the foot of the mountain within a time limit.

However, this time there was no need to bring Nezuko. Dan Lei had Sasaki Kojiro appear and watch from the foot of the mountain, while he and Urokodaki Sakonji went up the mountain together.

Here, Dan Lei didn't go up the mountain to watch Tanjiro's assessment process. Instead, after Tanjiro began his assessment, he took the opportunity on his way down the mountain to say something to Urokodaki Sakonji.

"Mr. Urokodaki Sakonji, please forgive my impertinence, but when you taught Tanjiro the breathing techniques, could you also teach me? I will repay you with my research data on demons."

Dan Lei's words caused Urokodaki Sakonji to stumble and nearly fall flat on his face. After regaining his balance, he retorted, clearly speechless.
"Lord Danlei, with a master like Lord Sasaki Kojiro at the Celestial Realm by your side, do you still need to learn breathing techniques from me?"

(End of this chapter)