With a reputation of 70,000, one leader travels across countless worlds with his adventure team.

"Zheng!"

Nakime activated Blood Demon Art in the Infinity Castle, sending all the Lower Rank Demons she sensed into the Infinity Castle space.

Lower Moon One, Nightmare, and Lower Moon Two, Rokuro, were instantly transported into the Infinite Castle. While the two bewildered demons were wandering around wondering where they were, they heard a "clang".

The two ghosts were instantly teleported to a woman wearing a kimono with red eyes and black hair.

While busy with his own affairs, Muzan sensed the impending death of Lower Moon Five, Spider Demon, but at that time Muzan was investigating the "Blue Spider Lily" somewhere. By the time Muzan launched the Lower Moon summons, there were only two Lower Moons left.

Muzan's face contorted with rage, causing the beautiful woman's features to distort with fury. He roared, "..."

"Give me a sigh!"

Only then did Enmu and Rokuro recognize Muzan from his voice and aura. Both demons trembled and swayed, but Lower Moon One Enmu was so captivated by Muzan's prestige and aura that a different kind of flush appeared on his demon face.

At that moment, the two demons heard Muzan's furious voice:

"Why are the Lower Moon demons so cowardly? Making you Lower Moons was just the beginning. Some of you trash took the blood I bestowed upon you as a means to survive. Now only two of you trash are left to come see me!"

Since only the two of you trash are left, then disappear! Any last words?

Lower Moon Two - Rokuro stood up, covered in sweat, and said:

"I am still useful to you, Lord Muzan. Now that those few useless trash are dead, Lord Muzan can reward me with more blood. If you could grant me some time, I will definitely..."

"How long should I extend this grace for you? How much help can you provide? Your power is currently insufficient to bring me pleasure or any information I desire, so why should I continue to bestow gifts upon you?"

And how dare you instruct me to give you my blood? You're utterly shameless!

After saying that, a giant fist of flesh and blood instantly appeared, crushing and devouring Lower Moon Two, Rokuro. Then, Muzan looked at Lower Moon One, Enmu, whose face was flushed but whose eyes were fearless, and asked:

"Is there anything else you'd like to say?"

Lower Moon One Enmu, her face flushed, clutched her cheeks and chuckled eerily:

"Ah~ This scene is like a dream. To be able to do it yourself, to be able to cry out in front of you, is such a happy thing. Ah~~~ How blissful!"

As he spoke, Lower Moon One Enmu opened his arms as if to embrace Muzan's attack. Muzan narrowed his eyes and lashed out with his flesh-and-blood whip, piercing Lower Moon One Enmu's neck and injecting more of his own blood into him.

Suddenly, Lower Moon One Enmu, whose body was flooded with Muzan's blood, writhed on the ground in agony, his body convulsing. Muzan, a smile playing on his lips, said:

"I've chosen you! Take my blood! But you might not be able to withstand it and explode, but if you can 'adapt', you can become even stronger."

Then lend me a hand, kill more demon slayers, wipe out those 'pillars' that demon slayers talk about, and make me even happier!

Muzan absorbed all of the Spider Demon's memories before his death. Tanjiro's final sword strike sent a shiver down Muzan's spine. Meanwhile, Hakutaku, who was frantically killing three Lower Rank demons, also came into Muzan's view. He then said:

"If you can kill the demon hunter with the flower-patterned decoration on his ear, and the pillar with white hair, red eyes, and wearing a white robe with red floral patterns, I will reward you with more evil blood."

With her face flushed and drool dripping, Lower Moon One Enmu looked up at Muzan, and then Nakime plucked the strings of her koto.

"Zheng!"

Lower Moon One: Nightmare was sent out of the Infinity Castle and appeared in a street passage.

Enmu saw the figures of Hakutaku and Tanjiro in Muzan's blood. Enmu held his face and muttered to himself:

"Find them, kill them, only in this way can I bring greater value to Lord Muzan, and only in this way can I obtain more rewards from Lord Muzan!"

 …

After sending away Lower Moon One, Enmu, Muzan sent a message to the Upper Moons who were away, instructing them to keep a close eye on Bai Ze and to kill him if they encountered him.

Over the next month, the Hashira of the Demon Slayer Corps began selecting outstanding members from their respective areas and, based on the principles outlined during their special training, taught them the Yi Jin Jing (Muscle/Tendon Changing Classic).

After the outstanding team members in their respective areas achieved results, the team members who had made significant progress in training were selected and taught the "Flame Blade" technique again.

Meanwhile, Lower Moon One, Enmu, was not idle either. He possessed the Mugen Train and ate people every day as the train came and went. Eventually, the number of missing persons became too large, which attracted the attention of the Demon Slayer Corps.

However, after several groups of scouts boarded the train at different locations, they disappeared without a trace, causing the Demon Slayer Corps to shift their focus to the Mugen Train. This time, Kagaya Ubuyashiki sent out the Flame Hashira, Kyojuro Rengoku, who had just returned for his rest, to investigate the situation.

They then sent messages to the three little ones near the Mugen Train (after Tanjiro got the sword, the three little ones went out to team up and fight demons. Because their functional recovery training was replaced by Hakutaku's special training, the three little ones left very early this time and did not receive the message at the Butterfly Mansion).

Afterwards, Kagaya Ubuyashiki had a premonition that this might also be a Twelve-String Demon Moon, so he had Kasugai Crow deliver information about the Mugen Train to Hakutaku as well.

To Kagaya Ubuyashiki's surprise, Hakutaku had already taken the four women and headed towards the Mugen Train.

 …

Back to the swordsmith village, the small crystals that Bai Ze brought back to Steel Tomb and Iron Cave Forest amazed all the master craftsmen. There were even crystals that could store elemental attributes, which was truly amazing!

Immediately afterwards, each of the swordsmiths took a different set of four-colored crystals back to study how to imbue these properties onto the Nichirin Blade without conflicting with the "Scarlet Sand Iron" and "Scarlet Ore".

At first, the swordsmiths were still figuring out how to fuse the small crystals into the swords. One swordsmith said:

"Why don't we try mixing the small crystals directly into the molten iron and see if it has any effect after the knife is successfully forged?"

The suggestion from the swordsmith reminded everyone, and then the swordsmiths directly incorporated the four-colored small crystals into the molten iron. The swords were indeed formed without any problems, and the swordsmiths also felt the special properties brought by the different small crystals on the weapons.

After using the swords crafted with the small red crystals, you can feel a warm sensation when you touch the blade. When you use the swords to attack objects, the places on the objects that are cut will show burn marks.

After testing the swords crafted using the small blue crystals, touching the blade will give you a cool feeling, and when you use the swords to attack objects, frost-like fragments will appear where the swords are cut.

After testing the swords made from the white crystals, you will feel a static shock when you touch the blade, and the blade will spark with electric sparks when you swing it.

After trying out the sword forged with the black crystal, it finally felt different. The swordsmith felt a different sensation when he touched the blade compared to the three colors of crystals mentioned above. The swordsmith was still wondering what the effect of the black crystal was.

At this moment, the knifesmith suddenly felt a wave of weakness throughout his body, and his stomach began to release gas. He couldn't stop the urge to vent from his anus.

The knife maker hurriedly called for help to go to the toilet. Before he could even tell anyone not to touch the knife he had made, he was already vomiting profusely.

At this moment, another swordsmith picked up the small black crystal sword that the previous swordsmith had forged and continued to study it. After a short while, the second swordsmith suddenly went limp, became dizzy and disoriented, and collapsed to the ground.

The second swordsmith hurriedly called for help, this time warning everyone not to touch the sword, for it was a "demon sword!"

(I infused the abnormal statuses from the dungeon onto the swords forged from the fused small crystals. Once the swords, imbued with the black small crystals, are completed, attacks that damage the opponent will apply a buff to them:)

A series of effects, such as poisoning, weakness, slowing, dizziness, and confusion, will be triggered randomly. The first swordsmith was slightly poisoned and started to have severe diarrhea, while the second one was confused.

Burning and bleeding were given to the sword forged from the red crystal; electric shock and blindness were given to the sword forged from the white crystal; slowing and freezing were given to the blue crystal.

In the end, the red, blue, and white crystals were successfully fused perfectly with the existing Nichirin Blade. Only the effect of this small black crystal on the sword gave the swordsmiths a great headache. This effect, which would attach to the body upon touching the blade, made everyone very wary.

The swordsmiths didn't give up their research, and finally discovered that as long as the handle was attached and the sword was held without touching the blade, the swordsmith wouldn't apply a buff to themselves.

Then the swordsmiths experimented with attacking living creatures with the four-crystal Nichirin Blade. They used a chicken they had raised for two and a half years as a test. When the small red crystal Nichirin Blade struck the chicken, it immediately set it on fire.

After making a few cuts, I found that the chicken was bleeding profusely. The more the chicken moved, the faster it lost blood. In just a few minutes, the chicken stopped moving.

The chicken, struck by the small white crystal Nichirin Blade, had its feathers crackling with electricity, and the whole chicken seemed to be performing a breakdance for everyone on the spot!

The chickens struck by the blue crystal Nichirin Blade moved slower, and frost appeared on their feathers. One of the chickens struck was instantly frozen into an ice sculpture, remaining in place in its pose.

Because of the contributions of two swordsmiths, the black version underwent the longest experiment and produced the most noticeable results.

Some of the chickens that were slashed began to have severe diarrhea, and soon the whole chicken collapsed on the ground and did not move; other chickens became dizzy and disoriented, and began to spin around on the ground.

Finally, the swordsmiths sent the news that the four types of crystals could be successfully fused into a Nichirin Blade to the head of the family, Ubuyashiki Kagaya, and explained the effects of each of the four types of crystals. They also presented him with several well-forged four-crystal Nichirin Blades.

A few days later, Kagaya Ubuyashiki, who had just received the new Nichirin Blade with four crystals, immediately summoned the Stone Pillar and the Insect Pillar to test its effects. Gyomei and Shinobu Kocho both praised the new blade's effects, saying that this kind of Nichirin Blade with its own attack capabilities would definitely give the demons a pleasant surprise.

Shinobu Kocho was particularly pleased with the Nichirin Blade fused with black crystals; she even had the urge to reforge her own blade and infuse it with black crystals.

Kagaya Ubuyashiki saw through Shinobu Kocho's thoughts and said with a sly smile:

"Butterfly, I'll give you a task then~"

Shinobu Kocho knelt on one knee and said:

"Please give your orders, my lord."

Kagaya Ubuyashiki said with a chuckle:

"You will be in charge of escorting this batch of small crystals to the knifesmith village. There, the knifesmith can remelt your knife."

I think the small black crystals are working really well for you!

Shinobu blushed slightly, her thoughts exposed, while the Stone Pillar beside her kept muttering "Amitabha...Amitabha" with a smile on his lips to prevent himself from laughing.

Shinobu Kocho blushed and replied:

"I will obey your orders and escort Little Crystal to the Swordsmith Village to complete the mission."

Kagaya Ubuyashiki nodded with a smile, then arranged for the Hidden Team members to pack and box the tens of thousands of four-colored small crystals that Hakutaku had left at his residence. Shinobu Kocho led a team of swordsmen, along with the Hidden Team members and the swordsmith who had come to deliver the message, back to the swordsmith village hidden in the mountains.

Afterwards, Kagaya Ubuyashiki gave the swordsmith village a task: first, to send a batch of four-crystal Nichirin Blades to all the areas guarded by the Pillars, and then to have the swordsmen in each area replace their swords and quickly test the damage effect of the new four-crystal Nichirin Blades on the demons.

They also instructed the Pillars to collect the effects of each crystal and determine which of the four small crystals was most effective against demons. They then planned to retain the crystals with the most significant effects, forge a large number of Nichirin Blades, and distribute them to the Demon Slayer Corps.

The Pillars were given a choice: to use their own breathing techniques combined with suitable small crystals to go to the swordsmith village to re-enchant their swords during their turn.

Half a month later, the Pillars who had successively tested the effects of the four-crystal Nichirin Blade sent their results to Kagaya Ubuyashiki. The red and white ones were the most effective against demons.

Even at night, slashing a demon with a red and white crystal Nichirin Blade is almost identical to slapping a demon directly in the sun during the day; the demon recovers very slowly from the burns and electric shocks.

When the blue crystal Nichirin Blade hits an Oni, it slows down the Oni's recovery speed, movement speed, and attack speed, but the effect does not last very long.

Apart from the Water Pillar Giyu Tomioka and the Mist Pillar Muichiro Tokito, who were very interested in fusing the blue crystal with the Nichirin Blade, the other Pillars did not choose the blue crystal.

The black effect is just like in previous tests; it's very strange. Which effect you trigger when you hit a demon is entirely based on luck. Some effects make the demon dizzy and miserable, while others make it difficult for the Demon Slayer Corps to pursue and kill it...

Because the ordinary ghost that ran ahead transformed into a jetpack warrior and sped away, the team members behind unanimously gave up the chase, thinking that they could find it and kill it by following the trail of its jets after daybreak.

Afterwards, the Stone Pillar, Wind Pillar, Love Pillar, and Sound Pillar all chose to find an opportunity to enchant their swords with small white crystals. This was the most direct way to paralyze and blind the demons, thus restricting their movements.

The Serpent Pillar's final report to Kagaya Ubuyashiki was a small black crystal. From now on, Obanai will not only have a venomous mouth, but his weapon will also be a venomous snake!

Since Flame Pillar Kyojuro Rengoku and the three little ones were still on their way to the Mugen Train, Kagaya Ubuyashiki didn't rush them to report, thinking he would wait until they finished dealing with the train issue before doing so.

Without a doubt, Tanjiro and the Flame Pillar, who use Sun Breathing, will definitely choose the red crystal, Zenitsu, who uses Thunder Breathing, will use the white crystal, and we'll have to ask Inosuke about his choice when he returns.