The protagonist is always amazing

A demon isn't that strong. 

Isao realized that fact after he had fought many of the strong demons. 

While a demon might give terror to everyone in this world, its existence was unable to shake the foundation of this world or become an existence akin to a disaster such as a tsunami or an earthquake that could easily cause billions worth of losses for humanity. 

At best, the demon was like a beast who ran away from the zoo. While a single human or few people were helpless against them, if many people gathered, those demons were as good as useless. 

While it was true that the strength among the demons might be special and could even match hundreds of people, it was impossible to match the might of a country. 

Or rather, as long as thousands of people gathered, Isao could imagine that Muzan could be defeated. 

However, if that happened, the story where the protagonist and other characters who show their hardship in their battle wouldn't appear. At the same time, the demon would be decimated immediately and become an object of research for immortality. 

Isao didn't doubt such a thing since sometimes a human was far crueler than a mere demon, who only ate a human occasionally. 

Still, he was so glad he came to Tanjiro; otherwise, would he have a chance to devour Muzan's DNA? 

'Well, since you are here, then I won't let you go.' 

Holding Muzan's head, Isao directly devoured it to ease the consumption of his energy from absorbing Muzan's DNA into his body. At the same time, he also absorbed all the other parts of Muzan's body, which he cut down, slowly but surely devouring everything of Muzan's. 

Still, Isao had to say that Tanjiro's fate was so miserable.

At the same time, Muzan was confused. 

What was happening?

Why did this happen?

Who was this? 

Those questions kept repeating in his mind as Muzan's body was mercilessly cut into several pieces. 

"Dance of the Ant: Swarms!" 

As his body was ravaged and cut into several pieces, he was unable to do anything. Muzan suddenly remembered being ravaged by the creator of the original breathing, Yoriichi Tsugikuni. 

At that time, Muzan was unable to do anything, and his body was cut so many times in that single moment that he could only run away in a pathetic way. Naturally, that experience made him careful, and he made his body immune from the Nichirin blade. Even if he was cut down, as long as a piece of his flesh remained and he wasn't basked in the sunlight, he would surely recover. Moreover, he also had seven hearts and five brains, so his survival was guaranteed. 

If there was something that could threaten him, it was the descendant of the original breathing, which was Tanjiro's family. 

As a demon who cared about his life well, he wouldn't allow the slightest threat on his life, so he killed the descendant of the original breathing. He was able to kill them at ease, and everything was about to move in a perfect direction, yet why was he about to die?! 

Muzan felt like he was inside a nightmare, and despair was about to swallow him into eternal darkness. This was his first time feeling like this, and the one who did this was an existence that he had never paid attention to. The existence who he thought could trample time turned out to be a sly hunter who waited to devour him! 

"AARRRRGGGGGHHHHHHHHH!!!!!" 

Yet, it could do nothing. 

No matter how he tried to escape, somehow, Isao was able to read his intention and cut all of his escape routes, killing him steadily and surely. At that moment, he was like an insect about to die, swarmed by thousands of ants. Even if he was able to kill one of the ants, another would come, overwhelm him with quantity, and bite him until he died and became the food for all of them. 

This was bizarre, something he had never felt before; it was the greatest crisis he had ever experienced!

Yet, when Muzan was in despair, Isao became stronger and stronger. This might be due to Tanjiro's DNA; the moment he was about to kill Muzan and achieve the dream that everyone had never been able to achieve for a thousand years, his body also grew stronger and stronger. 

Moreover, the memory that came from Tanjiro's DNA also sparked all the potential within his body. 

His blood-red violet weapons also radiated a bright red glow, and their temperature also increased even further as he ravaged Muzan's body into pieces! 

While Tanjiro saw all of this in a daze, everyone from the Demon Slayer Corps also came before they stunned in a place. 

Even Shinobu and Kanroji were also unable to react as they watched this fight. 

Muzan... while they didn't know what the rank of this demon was, they could tell that it was an extremely powerful demon, but Isao's prowess was that stunned them silly, especially Shinobu, as she had never thought her "Insect Breathing" could be developed by Isao this way. 

Yet, this wasn't something surprising, especially for Isao, who had the sword talent from Saeko, all the Hashira, and also Tanjiro. The combination of all of them had given them a frightening talent for swordsmanship! 

However, as they stared at this fight in a daze, they forgot to watch out for Tanjiro. 

At this moment, Tanjiro had woken up and quickly ran toward his family. Yes, he knew that Isao and Muzan were fighting, but his family was there! How could he watch his family be tramped by their fight? So, even if this was stupid, he decided to charge forward to bring all of his family away! 

"Wa-Wait!" 

"What are you doing?!" 

"STOPPPP!" 

Everyone tried to stop Tanjiro, but Tanjiro, whose body had exceeded normal human quality, couldn't be reached or stopped. He was already in front of his family and ready to take them away. 

Only Muzan saw this chance and made a desperate attempt to kill Tanjiro. 

Muzan knew this was a bet since he could tell Isao was an evil guy, and he probably wouldn't think of anything if Tanjiro lost his life. Still, no matter what, Isao was a Demon Slayer, and it was his duty to protect others, so as long as he tried to kill Tanjiro, then Isao would stop him! 

Muzan thought so, and he decided to make this bet. 

Though, he knew if he failed, then—

Once again, Tanjiro felt the threat of death and saw a blade-like arm about to fall into his head. His eyes widened, and his eyes were full of fear as he hugged his siblings tightly. However, like before, he was saved once again. 

"Dance of the Grasshopper: Death Hopper!" 

Suddenly, Isao's arm transformed and had the trait of a grasshopper's legs. Then, using the spear part of his poleaxe, he stabbed Muzan's body and slammed him into the distance with all of his might, yet at that moment, Muzan won. 

At that far distance, several pieces of his flesh gathered together into the size of a brain before a Japanese sliding-door-like portal appeared and pulled him inside, saving him from the crisis. 

Isao didn't bother to chase Muzan and just stood helplessly before he looked at Tanjiro, who was still stunned as he hugged his siblings like a frightened lamb. 

"Amazing..." Isao said helplessly as he looked at the night sky.