Ultimate Being from the Tokonosu City

Isao's skin was fair, and his body was in the perfect state with muscles that reminded anyone of Greek Gods. More importantly, he was extremely handsome. 

In an era when everyone's skin was bad, one could only rely on being healthy and the natural beauty of one's appearance to stay handsome or beautiful, as there were no beauty products or plastic surgery. 

In other words, it was almost impossible to see someone as handsome as him. 

Doma licked his lips when he saw Isao, thinking that this young man's flesh would be so tender and delicious. However, at the same time, he was also confused since, as a demon, he possessed an "Extrasensory Perception," an extraordinary sensory ability that allowed him to detect things outside the normal range of perception, so if one wanted to do a sneak attack on him, he would notice it immediately. 

'Well, it doesn't matter.' 

Doma thought that he was too focused on Kocho Kanae. Moreover, before, he had confirmed that there were no other people present, at least, no members of the Demon Slayer Corps other than Kanae, who was still alive in the surroundings. 

Everyone had died except for Kanae, so it was normal for him to relax his guard, especially when he knew that it was only a time before Kanae died. 

With all of those factors, Doma understood why he missed Isao, who could punch him undetected. At the same time, while he observed Isao's appearance, he also observed his breathing. 

'This... he isn't a member of the Demon Slayer Corps?' 

Unlike Kanae, who still maintained her unique breathing, Isao breathed normally, as ordinary people do. If there was something exceptional about him, it was the prowess of his natural physical ability. 

So, when Doma thought all of this, he couldn't help but cover his mouth with his hand, trying to hold his laugh. 

On the other hand, Isao, who had decided to replicate all the DNAs that he had acquired, knew which world he was in. 

Kimetsu no Yaiba. 

In simple terms, it was just a story about a human fighting against an evil being known as a demon.

Doma, the man before him, was that demon. 

More importantly, Doma was the third strongest, or someone with the third highest position among all the demons, which made Isao speechless. The moment he came to this world, he had to fight the third-strongest demon in the story. 

Was this world wishing for him to die? 

Fortunately, Isao was able to replicate their DNA; whether it was Doma or Kanae, he replicated them, but Kanae aside, he almost staggered when he absorbed Doma's DNA. 

His words almost seemed like he underestimated Kanae, but except for her knowledge of medicine, poison, "Flower Breathing," and other things, there was nothing exceptional about her body. Compared to his body, her body was much weaker, especially when she was a female and also had a graceful body. Even if she used "Flower Breathing," a unique swordsmanship used by the Demon Slayer Corps to fight a demon, he believed that he could win against her, so it wasn't a big problem for him to replicate Kanae's DNA. 

Yet, Doma, who was a demon, was different. 

A demon is a unique creature that exists in this world. They had exceptional abilities, making them capable of easily triumphing against any human. Fortunately, such a creature had a weakness, which was sunlight, or else this world might be ravaged by this creature. 

If it were a regular demon, Isao might not have felt much, especially since his body was enhanced with various DNA of animals that he had absorbed before. Along with his powerful and healthy body, an average demon would be as good as dead since it wasn't like a demon was that powerful. 

If Isao had to say, the demon might be like those "things," but with better fighting ability and a smarter mind, but their power wasn't much different. 

Yet, the one before him was the third strongest demon!

To replicate Doma's DNA onto his body, Isao's stamina was constantly drained, and his face became paler. Yet, the rewards he gained from all of this were immense, especially when he gained many of Doma's abilities, such as biological absorption, regeneration, immense durability, extrasensory perception, tessenjutsu (Japanese martial art with war fan), and even cryokinesis. 

If there was a problem, it was that he could not replicate Doma's unlimited stamina and endurance. 

Well, he could, but if he replicated this ability, he was afraid that he wouldn't even have the energy to stand up. There might be a chance he would recover quickly the moment he replicated Doma's unlimited stamina and endurance, but... would Doma wait for him to recover?

So, after Isao replicated some of Doma's abilities, knowledge, talents, etc., he quickly stopped it, waiting until he was in a safe place before he replicated everything. 

At the same time, Isao also realized the limitation of DNA replication, which was his stamina. If he was still a normal human like before, he wouldn't have been able to replicate Doma's DNA. However, as his body had become stronger, especially after he had absorbed the DNA of those "things" in the world of "High School of the Dead," he could do it. 

As Isao had said before, those "things" in the world of "High School of the Dead" had become new creatures that could live on forever without the need for food. They would keep living until their heads were smashed. He, who had absorbed the DNA of those "things," had inherited the advantage of those "things" and erased the disadvantage of those "things" on his body. 

Still, even if those "things" had immense stamina, they didn't have much endurance, and their stamina wasn't unlimited, so he couldn't perfectly replicate Doma's DNA in a short amount of time. 

Even so, facing Doma, instead of fear, Isao felt intense greed, wishing to swallow Doma's DNA since if he was able to do so, then he would become a perfect demon who wasn't afraid of the sunlight, which was something that the last antagonist of this world had never achieved. 

However, in the eyes of others, what they could see was only the nervousness and paleness on his face, which couldn't be hidden, and many thought that Isao was frightened by Doma. Yet, in the face of such adversity, he took Kanae's katana and held it with his right hand as if he were ready to fight Doma, showing the spirit of a young man who wished to save the young woman from her plight. 

"Oh?" Doma, who had been observing Isao, smiled. "You want to fight me? Are you sure? You have a burden on your hand, you know? While I know that this might seem arrogant, I am in the second-highest position, Twelve Kizuki. Oh, if you don't know, it is the twelve strongest demons, and I have the second highest position, or you can also say that I am the third strongest. Even so, do you still want to fight me with one hand?" 

Doma wasn't in a hurry. In his eyes, they were nothing but prey. He was like a cat who toyed with a group of mice. He could kill them anytime, but then again, it wouldn't be fun, so he wanted to see what this young man would do. 

Would Isao fight like this? 

Or would Isao abandon Kanae? 

Oh, Doma was curious~!

Yet, Kanae, who heard Doma's words, was anxious. She knew that Isao came because he wanted to save her, but she knew that Isao was just a normal human! Even if he might be powerful, he didn't master a breathing technique, and he knew nothing about the opponent before him! 

Moreover, as a member of the Demon Slayer Corps, it was her duty to protect everyone from the demon.

Lastly, their opponent was the third-strongest demon! 

Facing such a creature, what could they do? 

How could she let him die meaninglessly against Doma? 

"Go..." 

Even if her face was pale due to the blood loss, exhaustion, and wounds on her body, Kanae forced herself to tell Isao. "If you stay here, you will die. Just go. I will face him. It should give you more time to run away—" 

Doma smiled when he heard Kanae's speech, but inwardly, he had already thought about eating the two of them. Their relationship was nice, so wouldn't it be sad for them to be separated? 

'Oh, what a kind demon I am...' Doma thought silently. 

Yet, Isao's sudden action made Doma dumbfounded. 

Kanae was also dumbfounded since she was kissed! 

When Kanae was ready to sacrifice herself to Isao and fight Doma again, even if she knew she would lose, Isao kissed her lips! 

In this era, where the West hadn't influenced the culture of this country much, the act of kissing in front of the public was unheard of. 

Whether it was Kanae or Doma, they were dumbfounded. 

"Just shut up. Don't distract me." 

Isao licked his lips and thought Kanae's lips were strangely sweet, but there was a hint of distinctive iron, which should be something from her blood. 

While Kanae knew that this wasn't the time, she never expected to be kissed! In front of the danger where they could die anytime, this guy took her first kiss! 

Yes, Kanae might be Hashira (one of the leaders of the Demon Slayer Corps), and she might be one of the strongest demon slayers, but she was a girl who had never tasted love, especially when all of her life was spent revenge on her parents. 

However, the sudden bold act from Isao made her unable to calm down. Yes, she might die soon, but she didn't expect that she would lose her first kiss this way. Yet, watching his handsome, resolute expression and how he firmly held her on his arm... she didn't mind. 

"Wow!" 

Doma was so happy when he saw their act. "So bold! It's amazing! It's my first time seeing something like this in the past hundred years!" He even clapped his hands happily when he saw Isao kiss Kanae's kiss to shut her lips. It was a manly act that he had never seen before. "You guys are so nice~! Don't worry~! I will kill the two of you so you won't miss each other~!" 

Isao didn't say anything; his eyes were hostile, and he held Kanae's katana tightly, focusing on fighting Doma. 

Doma didn't care about Isao's hostility and was still in a leisurely position. He even waited for Isao to act first, giving Isao a chance to strike him down. 

Isao took a deep breath as if ready to fight at any moment, but suddenly, he turned and ran away. 

"...." 

Doma was in a daze, blinked his eyes in disbelief, and then watched Isao, who ran so fast like a cowardly rabbit, which was so much different from Isao's previous act. 

"This... is he running away?" 

---

Run away!

By the way, I have never asked, but do you like the world of the "High School of the Dead" and want me to focus on it? 

Though, to be honest, the story "High School of the Dead" is relatively short, and... the author is... well, you know, right? 

Still, if you want me to focus on it, I don't think it is impossible since there are many things that can be explored. 

However, everything also depends on whether it suits the story or not.

Or, whether I can think of the plot or not since I lack material for this "High School of the Dead."

Nevertheless, please enjoy~!