Even though Muzan would usually stay in Infinity City most of the time when he tried to recover, he also returned to the human world, as living in Infinity City for so long was quite vexing. Moreover, he could shapeshift his body into different genders and appearances, so it was impossible to guess his appearance.
At the same time, Muzan was living in Tokyo, a city where there were a million people.
In this big city, could they even find him?
Would they even guess that he lived in this big city?
Moreover, most demons would go to the countryside, which made the Demon Slayer Corps often go to the countryside instead of a big city.
Lastly, as he had disguised himself as a child, how could one find who he was?
At the same time, while he was in the city, he had ordered most of the demons to rampage around various corners of the country, giving a headache to the Demon Slayer Corps, whose numbers were just about hundreds.
Yes, he might not be able to face Isao directly, but it didn't mean that he would let Isao be happy, so he let his strong followers hunt down the Demon Slayer Members. He asked his followers to slowly torment them, killing them until all of them disappeared, especially those at the bottom.
Still, if there was something that made him a bit annoyed, it was that he couldn't find Isao's presence at all.
Whether it was Isao, Tanjiro, or the others who were present in the fight, Muzan couldn't find them.
Yet, at the same time, even if he found them, frankly, he might not dare to approach them, especially when he thought that it might be a trap set up by Isao to lure him out so Isao could kill him.
If Muzan could see what those demons that he had created see, then it was all fine, but unfortunately, he couldn't, and even if he could see the memory of those demons under him, they had to be so close to him. As he had ordered them to move far away, it was impossible for him to tell who they had faced or who had killed them, and it was too much trouble to visit the countryside to see their memories.
"Trash is trash, after all!"
Muzan missed Gyutaro, who could send his memory about Isao to him before his death.
Unfortunately, he didn't take Gyutaro's death and Isao's prowess seriously at that time, so he had to pay a heavy price for his mistake.
However, he wouldn't make such a mistake anymore, and he would wait patiently until Isao disappeared from this world. While he wasn't sure how old Isao was, he knew that he had only needed to wait for a decade until Isao passed away due to the "Demon Slayer Mark," so there was no need to be in a hurry.
'Still, what if he's like the creator of the breathing style?'
Like the creator of the breathing style, Isao might also be an exceptional human who could live past 25 even after he had the "Demon Slayer Mark," but even if he was one, it didn't matter since, for Muzan, who could live forever, waiting for hundreds of years were nothing.
This country was huge; he could hide inside the Infinity Castle and shapeshift into any different gender, appearance, height, and many others.
With all of those factors present, how could Isao find him?
Muzan was confident, and everything was foolproof. His plan was perfect, and it was impossible for anyone to find him. This was his confidence as someone who could stay alive for a millennium without being caught.
Still, as he walked around after he killed his wife, thinking about getting a new wife, he saw someone unexpected.
Tamayo...
Even though it had been hundreds of years since they had met, Muzan still remembered his servant, who dutifully followed all of his orders until they met the creator of the origin breathing, Yoriichi Tsugikuni, and betrayed him.
Until now, Muzan remembered how he was almost killed by Yoriichi, and he lost control of Tamayo. However, this time, it was different, as Yoriichi died, and Tamayo didn't know Isao, so when he saw Tamayo, he directly followed her quietly, thinking it would be nice to give her a little surprise after their reunion.
Yet, Muzan had to say that it was an excellent time.
Before the Demon Slayer Corps learned the breathing style, everything was peaceful, but after the breathing style existed, everything became uncontrollable, which made him even angrier and annoyed.
Still, Tamayo didn't seem to notice Muzan, and she just quietly walked toward her home, which was hidden by Yushiro's ability.
Yet, even if it was hidden, for Muzan, who had been following this stupid woman, it was something easy to do.
Then, when Tamayo had entered her house, Muzan talked for the first time. "It's been a while, Tamayo."
"—?!"
Tamayo was startled and looked at Muzan in fear, anger, hatred, and nervousness. "M-Muzan?!" Even if she had prepared, watching the demon, who had given her so much despair, how could she stay calm?
"Haha... is that what you should call me, my servant? You should submit, kowtow like a being that is lower than me!" Muzan loved to bully the weak since the weak wouldn't fight, and they were powerless against him.
Even if Tamayo had escaped his curse, so what?
Muzan could kill Tamayo as he wished to!
"Tamayo-sama!"
Naturally, Yushiro quickly came out, standing in front of Tamayo to protect her.
"Oh? How fascinating. Can you create your own demon?" Muzan was surprised by Tamayo, who could create a demon by herself. After all, even if the others could create a demon, they had to ask his permission, but Tamayo was able to do it without his permission. Unfortunately, even if she could, this demon couldn't escape his curse, and if he wished to, he could kill Yushiro whenever he wished.
Tamayo and Yushiro were clearly nervous, facing Muzan, who stood before them; it would be impossible to remain calm, but—
"Flower Breathing: Falling Wisteria."
Suddenly, something fell from the sky so suddenly that Muzan suddenly split in half.
Watching how gracefully and effortlessly Isao cut Muzan in half with his poleaxe, Tamayo and Yushiro were stunned. They knew how powerful Isao was, but Isao was a human, and as a demon, it was natural for them to underestimate humans, thinking that they were weak beings.
'So-So strong...'
Still, Isao didn't end Muzan and just stayed in a place for a while before, as expected, a portal with a traditional Japanese door-like design formed and pulled one of Muzan's body pieces.
Yes, Muzan ran away.
Muzan didn't expect Isao to use Tamayo as bait and cursed Tamayo's luck since this woman always had a strange fate that pulled a strong Demon Slayer that had the power to kill him.
Moreover, Muzan could feel that Isao had become stronger.
When Muzan met Isao, his only option was to run away, and he escaped with no hesitation in his movement, but when this portal appeared, Isao also slipped like a worm that crawled inside hardened soil, entering a small space smoothly.
Watching Muzan and Isao disappear, Yushiro sighed in relief. "Tamayo-sama are you okay?"
Yet, he couldn't hear Tamayo's answer since Tamayo had also disappeared!
"Tamayo-sama!"