Ultimate Being from the Tokonosu City

Before Isao returned to the world of "High School of Death," he had been thinking about what kind of company he should create first. After all, this was the Taisho Period, and the world wasn't as convenient as the modern world. There were also many wars and demons. 

In such a situation, what kind of business should he do first? 

There were many things that he could do, especially when he had the memory of the future. 

So, after much completion and devouring all the knowledge he gained from the professors at Tokonosu University, he decided to enter the fish industry, especially canned fish. 

During the Taisho Period, or, to be exact, 1920, while a refrigerator existed, its use wasn't widespread, and while Japan had started to modernize, it wasn't thorough. It was impossible to get a new technology such as a refrigerator this year. 

If the fish hadn't been sold or put into a room filled with ice, it would rot unless it was fermented or processed into another form, such as katsuobushi or dashi. However, production was limited, and the technology wasn't so advanced. 

Rather, the factories that processed fish were limited, especially when the technology was still being mastered by the West. 

If those fishermen didn't want the fish they caught to rot and become nothing, then they could only sell their fish to him even if the price was so low. 

With all of that, Isao decided to enter the canned fish business and directly acquired one factory before improvising for his factory. Moreover, food was the core of everything. Controlling the food meant that he controlled the lives of people. In this country, fish was also abundant, especially when this country was surrounded by sea, whether it was from the Sea of Japan, the Pacific Ocean, the Sea of Okhotsk, the East China Sea, and many others. A fish could also become anything, whether it becomes a canned fish, fish oil, food for animals, or many other things. 

Then, when everything was good, he could expand to other businesses, such as shipping, warehouses, machinery, coal, waste management, and many others! 

Still, while he was doing his business, he also developed a new ability that resulted from combining his ability with Doma's DNA. 

Due to Doma's DNA, he gained all the advantages of being a demon, and one of those advantages was the ability to control his body. If he wished to, he could make his body into the shape of a whip or even separate it from his body, controlling it remotely, then regenerating the losing part of his body with ease. 

This ability was amazing, but what he wanted to say was that he could shape this separated part of his body into something else, such as a bird. 

Yes, if he separated his finger from his hand, he could transform that finger into a crow, which was the DNA he had recorded inside his system. 

By then, what was happening? 

Isao could create a life! 

Wasn't it amazing? 

The discovery made him create many crows and other types of insects that helped him scout many parts of the country. 

Still, even if this ability was amazing, what was the use of it? 

After all, if he wished to, he could control animals or living beings whose DNA was recorded inside his body. While creating a life from the part of his body was amazing, it didn't have much fighting ability, and it was much faster and more economical to control others since creating a life from the part of his body took quite his stamina. 

While this stamina could be recharged by eating, as he had said before, using his ability to control those beings whose DNA was recorded on his system was much faster than recreating a new creature. 

Yet, since he used this method, there was naturally a reason why he used this ability. 

The first reason was that those living creatures were created by using part of his body; they were connected to him, and he could connect their senses to his mind. 

The ability to control beings whose DNA was recorded might be good, but Isao couldn't use their senses to monitor the scenery and the surroundings. If he wanted to learn their information, he needed to touch them to learn new information from their DNA or by listening to their story.

What was so bad about it?

It was bad because the animals he used as scouts would need to return to his side if they wanted to report. Moreover, not all the animals he controlled had a long life span, and in the long term, he might cause the extinction of those animals if he kept using them as tools without taking care of them. 

While he didn't care about their extinctions, he felt that it took so long for them to report their information to him, but the method of creating a new life with part of his body was different. 

As this new life was created by part of his body, naturally, its vision was his, its sense of smell was his, its sense of taste was his, its touch was his. 

In other words, whenever those creatures were, he could see, taste, smell, touch, whatever their senses felt like they were his senses. 

If Isao had made it even simpler, he could have used those creatures like a camera that could connect to his brain, which would have made him capable of real-time live streaming from their senses.

They were like AI drone spy robots in this era, he thought. 

Moreover, unlike real animals that would be frightened by the aura of the demon, those creatures wouldn't feel afraid. 

Yes, he developed this ability because of his meeting with Doma. 

If those creatures reminded him of Doma, then would he meet this third-strongest demon in this world? 

Isao could win Doma because Doma underestimated him, but with Doma's defeat, would the demon give him another chance? 

He might erase the connection of Doma with other demons, especially Muzan, but it wouldn't hurt to be careful, right? 

Moreover, since Kagaya wished him to be part of the Demon Slayer Corps, Kagaya might leak his information to demons and make those demons target Isao, so Isao had no choice but to join the Demon Slayer Corps if Isao wanted to regain his peace. 

"The demon is great." 

Yet, at the same time, Isao wished to devour those demons more since his gains were so great that he became greedy for their abilities. The demons' abilities were unique, and all of them could make him stronger. 

Isao might be able to control a human, but they might be targeted, and they might also alert the demon, so those small animals that he had created were necessary for him to find those demons that had unique abilities to expand his arsenal and make him stronger. 

In the eyes of others, those demons might be harmful and even a disaster, but for him, they were incredible treasures! 

Still, compared to those demons, Isao was more concerned about the protagonist of this world, Tanjiro Kamado. 

When Isao replicated Takashi Komuro's DNA, he didn't think that something special would happen, but he was wrong. The body constitution of the protagonist was built differently, especially luck. 

The power to grow from nothing to a hero. 

If Isao didn't replicate Takashi's DNA, would he be able to become stronger and defeat his enemy? 

If he hadn't had Takashi's DNA, he might have only met Doma, and he didn't meet Kanae Kocho, who gave him the ability to "Flower Breathing." 

By then, what would happen to him? 

Tasting the sweetness that came from replicating the DNA of the protagonist, how could he let go of the protagonist of this world? 

If Isao could replicate Tanjiro's DNA, then would those demons escape from him? 

Instead, they would all become something that made him stronger! 

Lastly, the potential of the protagonist has always been amazing, and his goal to become an ultimate being naturally would become even closer! 

So, Isao used those creatures to search for Tanjiro. 

'Come on. Don't let me down.' 

Watching the crows, which were made, soar toward the sky as they searched for the protagonist of the entire country, Isao was full of expectations for the future. 

It was his first day returning to this world, but even so, he spent so long working on various things, from business to searching for the protagonist. He also told his followers to collect a variety of animals so that he could make himself stronger. 

Still, as he was in his office, working on various things, his followers, whom he had gained from using his ability to control, suddenly came and told him great news. 

Feeling curious, Isao followed his followers, who told him there was a surprise that would make him happy. Still watching an enormous blue whale that had been caught on the port, he took a deep breath and then smiled. "Good job."

'Ah... I love this world!' 

So with all that, Isao spent so long working before dragging his body back to his home. 

Along the way, while the light wasn't as bright as the one in modern times, the world was no longer in the darkness. 

Isao returned to his house, but he frowned when it was all dark, and it confused him since Amane shouldn't be inside.

Did she go home?

However, Isao could smell the scent of Amane from inside, and with his perception, he could tell that there was one person inside his house, and this person was obviously Amane, but what was she doing? 

After he parked his car, he entered his house but was dumbfounded. 

"Welcome back." 

From the darkness, Amane bowed and welcomed him like a good wife. 

"...." 

Kagaya... 

Whose wife was Amane again?