Ultimate Being from the Tokonosu City

On his arm, Kanae, who was ready to die with Isao, was stunned silly since she didn't expect that Isao would run away! 

With a handsome, resolute, unyielding expression, Isao ran away as fast as he could! 

Kanae felt like her worldview was twisted, and she had never expected that someone could run away with such an expression. 

"Hey, what was with the swordsmanship that you used to fight that guy before?" 

"Ah!" Kanae was startled when Isao suddenly questioned her, but probably because of how nervous, dumbfounded, and shy she was from her first kiss being taken so suddenly that she couldn't react for a while. 

"Hurry up and answer me! That guy is chasing after us!" 

While Isao didn't turn his head, he could tell that Doma was chasing after them at the fastest speed. Still, even so, he didn't feel nervous. Instead, he was happy since his plan was successful, but then again, all the preparations hadn't been completed, and he had to wait for a while before he could devour Doma. 

Kanae didn't understand why Isao suddenly asked such a question, but she answered him honestly, "That's a Breathing Style. It is a special swordsmanship used by the Demon Slayer Corps." 

"How to use it?" 

"...." 

Kanae widened her eyes and quickly realized what Isao planned to do. "Do-Do you plan to learn it now?!" How could she not be surprised? On average, one needed a few years to learn the Breathing Style. Even the most genius Hashira currently, Muichiro Tokito, needed two months to master the Breathing Style, yet Isao told her that he wanted to learn it now. 

At that moment, when they were chased by the third strongest demon and when they could die anytime, Isao said that he wanted to learn the Breathing Style?!

Yet, even though it was unbelievable, Kanae told him everything. Why? It was because she trusted him. The moment he held her, running away, without leaving her, she trusted him with everything, and another reason was because of that kiss. 

When they kissed, she felt like she understood him. She didn't understand the reason, but she just did. 

"It's like this..." 

Even if their time was limited, Kanae told him how to use the Breathing Style and even showed him how to use it by using her sweet lips, showing how to use this technique. 

While Isao had learned this technique after he replicated Kanae's DNA, he needed an alibi as to why he could master this technique. Yet, he had to say, he felt like everything was so smooth. He felt like he could use all the techniques that Kanae had mastered and even do it better. 

Was it all due to Saeko's talent? 

If Saeko had been born in this world, Isao could have imagined that she could have become the strongest sword wielder, and Isao, who had replicated her talent, could also have that possibility. 

Or rather, he could be even better! 

"Hey, hey. Why did you run away so suddenly? I thought that you would fight me, but you ran away. It was interesting, but you ruined the mood, you know?" 

As the third strongest demon, Doma could chase after them with ease. Even if he had admitted that Isao's running speed was as fast as Usain Bolt's, it was still within a human limit. As a demon, there was no such limit for him, and Isao had a burden on his arm, so naturally, he could chase after Isao. 

"Geez, what a letdown. I will send you off now." 

Doma was a bit disappointed with Isao. He thought that Isao would die beautifully, fighting with his everything. Unfortunately, Isao decided to run away. This time, he wasn't going to wait anymore. He was going to end the two of them and then eat them right away. Yet, even if Isao was weak, he was going to remember him since even if everything was hopeless, Isao had never intended to let go of Kanae, showing how admirable his spirit was. 

"Don't worry. I will make it painful for you." 

Suddenly, Doma increased his speed and appeared behind Isao before he swung his war fan, ready to smash Isao's head into minced meat. Everything was under his control, and Isao was just an ant that he could crush anytime, yet suddenly—

Isao's lungs suddenly expanded, and the air from outside was all sucked into his body. His blood flow and heart accelerated, causing his body temperature to increase to an unbelievable level. 

Isao felt his entire body excited and full of power. 

Yet, he also knew the danger of this technique since it drained his vitality, and he might even die young due to using this technique, so he knew he had to devour Doma. 

As long as he devoured Doma, then the problem that came from the Breathing Technique would disappear! 

Suddenly, his eyes became fiercer, and the world suddenly moved slowly. At the same time, an exquisite and elegant red spider-lily-like mark appeared on his neck. It was like a tattoo, but it was finer and naturally formed. 

Yet, Isao didn't notice that. Instead, what attracted his attention the most was how the world suddenly became slow, and he felt everything became clear and transparent. It was a wonderful feeling, yet at the same time, he could tell his vitality was drained significantly. 

However, Doma never realized all of that. His war fan was about to hit Isao's head, and the victory was in front of his eyes, so even if he noticed a strangeness on Isao's body, there was nothing that this young man could do but—

"Flower Breathing...." 

Isao's waist twisted at an unbelievable angle, jumping lightly, dodging Doma's war fan strike gracefully like a cat that fell from a high height smoothly and safely. 

Still, in the eyes of Kanae and Doma, the two saw his body move gracefully in the air while surrounded by delicate peach flowers. 

"Sixth Form: Whirling Peach." 

On the air, holding Kanae on one arm and holding katana on another, Isao spun around, using his momentum and body weight, swinging the blade of the katana onto Doma's neck.

Doma didn't even react, and his neck was cut directly, separating it from his body. 

"Eh?" 

Doma, who was still in a daze, was dumbfounded. His world also became slower, and he was still in disbelief. 

What is happening? Why is my head in the air? Why is my head separated from my body? 

Many questions appeared in Doma's head since Isao had never shown a killing intent, and the delicious meat that he was about to eat suddenly struck him down like a Venus flytrap that suddenly snapped shut on the unsuspecting prey. 

Watching this, Isao landed smoothly on the ground, still holding Kanae by his arm. 

Meanwhile, Doma also quickly reacted and tried to connect his head and neck once again, hoping to save his life at the last moment. 

However, the demon's reaction time was much slower than Isao's.

Reaction time. 

It was a moment that was needed for one to react. 

The average reaction time for humans is 0.25 seconds for a visual stimulus, 0.17 for an audio stimulus, and 0.15 seconds for a touch stimulus. 

As a demon and the third strongest, naturally, Doma's reaction time could reach 0.15 seconds with ease. This was the fastest speed, and it definitely could have saved his life at the last moment. 

However, Isao, who had absorbed the DNA of a fly, an animal with the fastest reaction time, Doma's reaction time was nothing. 

Scientists have measured a fly's reflex response time to be less than five milliseconds or 30 times Doma's reaction time! 

Along with his vision, which came from a combination of a cat's eyes, a dog's eyes, a fly's compound eyes, and a cockroach's sensor capable of sensing airflow to move instantly, when Doma's brain sent an order to his body to heal, Isao had already made his attack. 

"Flower Breathing Fifth Form: Peonies of Futility." 

Isao's arm bulged, gaining the power of an ant that was capable of lifting 50 times its own body weight onto his body before he moved swiftly and gracefully, unleashing a flurry of nine consecutive attacks that flowed and weaved in on themselves, simultaneously slashing Doma's upper arm, collarbone, windpipe, temple, diaphragm, rib, testicles, and thighs. 

Yet, this wasn't the end. 

"Flower Breathing Fifth Form: Peonies of Futility! Flower Breathing Fifth Form: Peonies of Futility! Flower Breathing Fifth Form: Peonies of Futility! Flower Breathing Fifth Form: Peonies of Futility! Flower Breathing Fifth Form: Peonies of Futility!" 

Isao kept repeating this attack on Doma several times without stopping until he was sure that this guy had truly died. 

"Eh?" 

This was probably Doma's only thought. His brain was unable to process what was happening, and the moment he realized that he had died, there was nothing he could do since Isao was too fast. 

Meanwhile, on his arm, Kanae widened her eyes, only to see something blurry before Doma was cut into several pieces. However, after she saw Doma die, Isao fell to the ground, but before he fell, he acted as if he had passed out, but he never let go of Kanae on his arm. Still, at that moment, when he fell, his hand moved strangely, reaching all Doma's cut meats and absorbing them into his body. 

As Isao replicated Doma's ability to absorb human bodies through physical contact, it was even easier for him to absorb Doma's DNA. 

[You have acquired Doma's DNA.]

[Do you want to absorb it?]

There was no hesitation, and Isao closed his eyes, enjoying the process of making his body even stronger. 

However, Kanae panicked when she saw that Isao had passed out. "Hey, wake up! Wake up!" Unfortunately, she couldn't hear his response, but fortunately, several voices were heard from the distance. 

"Kanae-nee-san! Where are you, Nee-san?" 

"Kanae-san! Please answer us!" 

"Please respond to us!" 

Kanae, who was desperate, quickly shouted, "Here! I am here! Hurry up and save him!" 

Watching several people quickly come, Kanae sighed in relief and closed her eyes, losing consciousness. She knew that Isao would be all right, but she had to say that even if her body was a little cold due to the blood loss, she felt warm. 

As the group of people came to save them, dawn was coming.

The sunlight erased all the darkness in the world, and several voices came from the distance, watching two figures who fell on the ground while hugging each other.