Nagi began to issue commands to Nakime. She blankly plucked her biwa a few times, and in an instant, the Love Hashira, the Serpent Hashira, and the Stone Hashira, who had been searching for Muzan elsewhere in the Infinity Castle, were all teleported to Tanjiro's location.
This was Nagi's strategy. Better to cut off one finger than to injure all ten. Rather than let all the Demon Slayers get separated and fight the Upper Ranks individually, it was better to concentrate their forces and take one down first.
Before Nakime was brought under control, the Demon Slayers had been lost in the Infinity Castle, playing a game of hide-and-seek, killing off the Lower Ranks or unranked small fry one by one, their stamina being slowly drained.
"Hm? Shinobu is in danger? No, I have to go."
Nagi sensed that the formula he had left on Shinobu's body had been activated. He quickly created a shadow clone to control Nakime. "I'm counting on you. After Tanjiro and the others eliminate Akaza, gather everyone and go after Muzan."
The shadow clone nodded. "Leave it to me."
With a flicker of the Flying Thunder God, Nagi vanished from Nakime's side.
"Kaigaku! It's all your fault! You're the reason Grandpa had to commit seppuku, you bastard!"
In a room somewhere in the Infinity Castle, the yellow-haired Zenitsu, upon entering, had used his protagonist-level superhuman hearing to find the person he hated most in the entire fortress: Kaigaku.
"Do you have any idea how long the agony of seppuku lasts when there's no one there to deliver the final blow?!" Zenitsu roared, tears streaming down his face. "Because of you, Grandpa, filled with guilt, committed seppuku alone, without a second. He died in agony! You bastard, you killed Grandpa!"
The "Grandpa" Zenitsu spoke of was, of course, the retired former Thunder Hashira. Because his chosen successor, Kaigaku, had betrayed them and become a demon, the retired Hashira had, out of shame, chosen to quietly take his own life. And his other successor, Zenitsu, had been so traumatized by the event that he had even lost his dual personality.
"Hahaha! So the old man's dead. Who cares? I only care about myself. As long as I can live freely, why should I care about anyone else? But you, you piece of trash who can only use the First Form, you actually dare to say your senior's name? You've gotten bold, haven't you?" Kaigaku laughed wildly.
He was a classic egomaniac, a pure egoist. What was his teacher's death to him? Sooner or later, everyone dies. Not like him; he would live forever.
Zenitsu's face twisted in a snarl. "If I'm a piece of trash who can only use the First Form, then you're a piece of garbage who can't even use the First Form! We're both failures!"
Kaigaku's expression turned sinister, his demonic features growing even more ferocious. "Is that any way to talk to your senior, you crybaby? Let your senior teach you a good lesson!"
With that, the powerful explosive force of Thunder Breathing made him vanish from the spot. He swung his sword at Zenitsu, and Zenitsu drew his own blade to meet him.
It was as if it were a matter of personality compatibility, or perhaps the arrangement of fate. The exceptionally talented Kaigaku had learned all the forms of Thunder Breathing, but for some reason, he could never master the First Form. Zenitsu, on the other hand, was the opposite. He could only master the First Form and couldn't learn any of the others.
"Thunder Breathing, Sixth Form: Rumble and Flash!"
Kaigaku used the strongest form of Thunder Breathing, but something unexpected happened. The Zenitsu he struck was just an afterimage.
"Thunder Breathing, Seventh Form: Honoikazuchi no Kami."
A figure cloaked in golden lightning flashed by, faster and more explosive than him. By the time he realized what had happened, his face was pressed against the ground. He had been beheaded.
"How is this possible?! That damned old man... he was still hiding a final form? He taught it to you, but not to me? That damned old man!" Kaigaku, his body beginning to burn, cursed his teacher with his dying breath, his face a mask of disbelief.
Sheathing his sword, Zenitsu looked at Kaigaku, tears streaming down his face. "You're wrong, Kaigaku. This form... Grandpa didn't teach it to me. I created it myself."
"H-how can that be?" Kaigaku looked on in disbelief as his head slowly burned away. "I... lost... to this piece of trash..."
The battle between Shinobu and Doma had reached its final stage.
Shinobu's blade could only inject 50 grams of poison at a time. This amount of poison was easily broken down and expelled by Doma's incredibly powerful demonic body. Her scabbard contained hundreds of different wisteria poisons, and every time she sheathed her sword, she would mix a different formula to use against him.
But the more she did this, the more fun Doma had. He clearly had the strength to kill her, but he kept provoking her, encouraging her to use even more potent poisons against him.
Finally, Shinobu unleashed all her strength, pinning Doma's head to the floor. Doma was moved to tears, and he hugged Shinobu tightly.
"You've worked so hard. You've really worked so hard. You truly move me. A girl who works as hard as you fully deserves to become one with me. I must grant you eternal life!" Doma cried, hugging Shinobu with all his might. His body had already transformed, a giant mouth appearing, ready to swallow Shinobu whole.
Crack! Just as several of Shinobu's bones were broken by his embrace, something changed.
As Shinobu gritted her teeth and glared at Doma, her eyes suddenly turned red.
A Sharingan pattern appeared in her pupils, spinning rapidly for a moment before unleashing a black flame. Doma, caught off guard at such close range, was hit directly.
Amaterasu!
Transcription Seal. One of the Uchiha clan's dojutsu, passed down for centuries. Like the Susanoo, it was different in that it could be placed by a Mangekyo user into another person's mind, to be triggered under specific circumstances. Itachi had used it twice: once to seal Shisui's Kotoamatsukami into Naruto's body as a counter against Sasuke, and once to seal an Amaterasu into Sasuke's eye as a counter against Obito. The Uchiha clan had passed down many ninjutsu unique to the Sharingan: Susanoo, Izanagi, Izanami, Transcription Seal. Some required the Mangekyo to use, while others could be used with just a three-tomoe Sharingan.
The day he had met with Shinobu, Nagi had hidden an Amaterasu in her eye. If she were ever in mortal danger, the jutsu would activate. It was difficult to dodge even from a distance; at this close range, the death-seeking Doma had no chance.
"Ahhh!" Doma threw Shinobu aside and frantically tried to bat at the black flames on his body. However, these black flames were not so easily extinguished. No matter what he did, he couldn't put them out.
The moment the Amaterasu was triggered, Nagi sensed it. He teleported to the battlefield in an instant, catching Shinobu just as she was about to hit the ground.
"Are you alright? I'm sorry, I'm late," Nagi said apologetically. Nakime's abilities were too annoying. Without dealing with her, fighting in Muzan's stronghold was too much of a hassle.
"Cough, cough. I... I'm fine. It's a pity... he didn't get to eat me," Shinobu said, spitting out a large mouthful of blood, a look of regret on her face.
"I told you, I can help you get your revenge. You don't need to sacrifice yourself," Nagi said earnestly. He placed his palm on her, and a green light of medical ninjutsu began to heal her wounds.
"Sister!" a heartbroken voice cried out. It was Shinobu's sister, Kanao. "Sister, are you alright? Don't scare me!"
"Aaaah! You bastard! I'll kill you!" From beside Kanao, a bare-chested man in a boar mask charged forward. It was Inosuke. The two of them had coincidentally run into each other in the Infinity Castle. Kanao, who had been worried that her sister would still go through with her foolish plan to poison Doma with her own body, had asked Inosuke to use his spatial awareness to lead her here.
Doma, however, calmly hopped backward, waved his fan, and unleashed his unique Blood Demon Art.
Blood Demon Art: Crystalline Divine Child.
Two small ice figures, identical to Doma, instantly appeared and engaged Inosuke and Kanao. Not only did they look like Doma, but their abilities were not far off from his either. For a time, they fought to a standstill.
"Ice clones?" Nagi frowned. Doma's Blood Demon Art was clearly a form of ice clone, and they seemed quite durable, comparable to a wood clone's defense.
"Oh my, oh my. What's with these flames? Why won't they go out? It hurts so much! What a pain!" Doma had a pained expression on his face, but his eyes were still as cold as ice. "I have no choice. Blood Demon Art: Wintry Icicles!"
Two lotus flowers made of ice, in the shape of young maidens, appeared on the battlefield. The ice maidens blew freezing air from their mouths, creating a large-scale freeze to try and extinguish the flames on Doma's body. However, to Doma's frustration, while the cold air suppressed the black flames, it still couldn't extinguish them. The flames clung to his body like a stubborn parasite.
"Ah, I've got it! I can just get rid of my body! Hee hee, I'm so smart!" Doma clapped his fan happily. He used his Blood Demon Art to suppress the Amaterasu flames below his chest, then swung his fan and sliced off the lower half of his own body, leaving only his head and one arm.
Seeing this, Inosuke and Kanao saw a glimmer of hope. They wanted to kill him before his body could fully regenerate.
Inosuke roared, "Beast Breathing, Tenth Fang: Whirling Fangs!"
Kanao, knowing it would cost her her sight, used her final form. "Flower Breathing, Final Form: Equinoctial Vermilion Eye!"
Unleashing their full power, they instantly dispatched Doma's ice clones and charged at his real body.
Doma, with only a head and one arm left, had a terrified expression. "Oh my, don't come over here!"
"Die, you bastard!"
Clang!
Just as their Nichirin Blades were about to slice Doma's neck, a colossal ice figure blocked their path.
"What... is this thing?"
Inosuke frantically sawed at it with his Nichirin Blade, but he couldn't break through its defense.
Doma, lying within the ice giant, no longer had his terrified expression. He said to Inosuke with a playful grin, "Hee hee. No more pretending. This is the strongest form of my Blood Demon Art, you know. Blood Demon Art: Rime-Water Lily Bodhisattva."
Blood Demon Art: Rime-Water Lily Bodhisattva. A ten-meter-tall ice statue of a Bodhisattva.
"A Water Lily Bodhisattva? You're piloting a Gundam, are you? What a coincidence. I have a Gundam too. I wonder whose is stronger?" a contemptuous voice came.
Hm?!
Doma looked up in the direction of the voice. A flame giant, twice the size of his own, appeared before him.