"A fine blade. I am Akaza, Upper Moon Three."
Akaza had just finished speaking when he licked the hand that the Flame Hashira had split in two down the middle. With a flick of his wrist, it was completely repaired in less than a second. The other fist, which Uchiha Nagi had severed, also regenerated fully in an instant.
However, the Flame Hashira didn't reply, merely asking, "Why would you attack an injured person? I cannot understand."
"It's nothing. I simply despise the weak. He was getting in the way of my conversation with you," Akaza said with a smile. "You're a Hashira, aren't you? The fighting spirit emanating from you is highly refined, nearing the supreme realm. I have a suggestion: how about you become a demon with me? If you become a demon, you'll no longer have to worry about your body aging. You can eternally enjoy the pleasure of growing stronger and fighting."
The Flame Hashira stated, "I have nothing to say to you. Though we've just met, I already despise you. I am the Flame Hashira, Rengoku Kyojuro. A Hashira of the Demon Slayer Corps would never join the demons."
"As long as you are human, you will age, you will die. You can never reach the supreme realm." Akaza sincerely extended a hand to the Flame Hashira. "Become a demon, Kyojuro. If you do, you can train for a hundred, even two hundred years, as you please."
Uchiha Nagi: "......."
Uchiha Nagi realized he seemed to have been underestimated. His opponent clearly possessed some kind of perception, sensing Rengoku Kyojuro's incredibly powerful body and strength. Uchiha Nagi, on the other hand, had only recently learned Breathing Styles. His body utilized chakra, which was like a reservoir of energy that could be drawn upon when needed, but it didn't register as fighting spirit to Akaza's senses. Coupled with the fact that Uchiha Nagi's physical body wasn't exceptionally strong, he was directly overlooked by Akaza.
Still, it wasn't entirely wrong. Flashy ninjutsu was fundamentally useless against an undying body that could regenerate in a second.
"I refuse," Rengoku Kyojuro declared, his voice unwavering. "Growing old, getting sick, and dying—though life is fleeting, that is precisely the beauty of human existence. It is because humans age and die that life is so sacred." He continued firmly, "I will say it again: our values are vastly different. No matter what reason you offer, I will never become a demon."
"Is that so?" Akaza said regretfully. "What a disappointing answer. If that's the case, then I'll let you die in your prime."
He then stomped heavily on the ground, thrust one palm forward, and a snowflake-patterned fighting spirit emblem materialized around him.
"Destructive Death: Compass Needle!"
With a tremendous roar, he lunged towards the Flame Hashira, Rengoku Kyojuro, at a blinding speed that Uchiha Nagi's body couldn't possibly follow.
"Hahahaha! Among all the Hashira I've killed so far, there hasn't been a Flame Hashira! And no one has ever accepted my invitation~" Akaza laughed maniacally as he unleashed his fist techniques upon Rengoku Kyojuro. He paid no mind even when Rengoku's blade struck his fists or body head-on, because, aside from his neck, he had no weaknesses. Strikes to his head or heart would regenerate in a mere second.
Rengoku Kyojuro, however, was constrained. Besides finding a way to strike Akaza's neck, he constantly had to defend. Because a human body, once injured, couldn't heal in an instant.
"Hahahaha! Out of respect for the strong, I will use my full power to ensure you die without regrets!" Akaza roared with laughter. "Destructive Death: Air Type!"
"Argh..." Rengoku Kyojuro grunted in pain. Akaza's Air Type was an invisible attack; he had merely punched the air, yet Rengoku was hit, as if by an air cannon.
"Flame Breathing, Fourth Form: Blooming Flame Undulation!" Rengoku countered, unleashing a swirling vortex of fire.
Uchiha Nagi didn't intervene. Firstly, he couldn't keep up with their speed. Secondly, the Flame Hashira's original fate was different here; he currently still had his full stamina. Thirdly, Nagi had discovered something astonishing: Akaza's techniques weren't purely Blood Demon Arts; Nagi could copy them.
That's right. His opponent's martial art, which resembled a manifestation of fighting spirit, was an ancient practice in this world. It had only gradually declined because demons became unkillable, and later, with the strongest swordsman creating Sun Breathing, it was slowly replaced by Breathing Styles. Now, Uchiha Nagi found he could perfectly replicate Akaza's techniques and unleash them using chakra. The only drawback was that his physical resilience couldn't match Akaza's, so the power he could generate might not be as great.
If I create distance, I won't be able to reach his neck. In that case... Rengoku Kyojuro had also realized this. If he distanced himself from Akaza, the demon's stamina was limitless, while a human's physical strength was finite and would only diminish as the fight wore on. Close combat was his only chance for survival.
"Flame Breathing, First Form: Unknowing Fire!"
The First Form: a super-fast charge with the momentum of a fiery explosion, instantly bringing him before Akaza, his blade slashing towards the demon's body.
Yet, in the next moment, Akaza gave a savage grin, his wound healing in half a second. "Such excellent speed. Let this brilliant swordsmanship die here with you."
Tanjiro struggled to get up and help, but Uchiha Nagi stopped him. "Tanjiro, you guys can't keep up with his speed. Stay here and don't interfere. I'll go help," Uchiha Nagi said.
After some analysis, Uchiha Nagi concluded that Akaza was remarkably similar to Guy with his Eight Inner Gates opened—invincible in both ranged and close combat. Uchiha Nagi had never seen Guy open the Gates, so he didn't know how many Gates Akaza's power was comparable to. But Akaza had one advantage over Guy: his demonic immortality was superior. Moreover, Akaza wasn't like Guy, who would be incapacitated for half a month after keeping the Gates open for ten minutes. Akaza could maintain this state for an entire night.
Their battle had already spilled into the forest. From within, tremendous roars echoed intermittently, accompanied by flying splinters of wood and clods of earth. Finally, the Flame Hashira, Nichirin Blade in hand, was kicked out of the woods, landing with a roll.
Rengoku Kyojuro was already panting and sweating but hadn't sustained any serious injuries. In contrast, Akaza emerged from the forest with a smile, one arm severed. The next second, with a flick, the arm regenerated completely from the stump. Not a trace of fatigue could be seen on Akaza's face.
"Become a demon. Then you won't feel tired, nor will you fear injury."
"I refuse! I'll say it again, I despise you! Flame Breathing, Third Form: Blazing Universe!"
Facing the Flame Hashira who had slashed his body at incredible speed, Akaza's eyes showed only excitement, not a hint of pain. The wound healed perfectly in the next instant.
"Truly excellent! Such a beautif—"
Akaza hadn't finished speaking when an unexpected development occurred.
"Earth Style: Headhunter Jutsu!"
A Shadow Clone, which had been lying in wait stealthily, emerged from the ground, its hands shooting out to drag Akaza down into the earth. This sudden turn of events caught Akaza slightly off guard.