"Crap…"
Meanwhile, Naofumi Iwatani, who had been dragged into the Infinity Castle along with the Prison Shields, was watching the two massive shields plummet through the void. He knew he couldn't abandon the Ubuyashiki family trapped inside.
If only his companions were here…
That thought crossed Naofumi's mind—he remembered Raphtalia, remembered Filo… and the new companions he had just met: Kairo Retsu and the others.
But he didn't hesitate. He acted.
"Deactivate: Prison Shield!"
Naofumi forcibly dispelled the Prison Shields, revealing Kagaya Ubuyashiki, his wife Amane, and their two daughters—still unaware of what was happening.
Save for the already-blinded Kagaya, the others were just regaining their senses when they saw Naofumi, bearing a fierce expression, using the massive recoil of his Heavy Bowgun to maneuver his broken body closer.
He gathered the Ubuyashiki family together, then extended his right arm and activated the power of the Four Cardinal Shield:
"Prison Shield! Energy Shield!"
This time, the massive Prison Shield enveloped all five of them, and the Energy Shield formed beneath it, trying to soften the fall.
"Energy Shield! Energy Shield! Energy Shield! Energy Shield! Energy Shield! Energy Shield! Energy Shield!!"
Naofumi didn't care about stamina consumption anymore. Clenching a piece of [Well-Done Steak] in his left hand, he tore into it to replenish energy, while his right hand furiously spammed Energy Shields.
When the Prison Shield finally came to a halt and dissipated, Naofumi collapsed to one knee, feeling the dual effects of exhaustion and recovery crashing over him.
"Kagaya Ubuyashiki… I hope what Granny Felyne said really works."
He wasted no time. Recalling the contingency plan he and Kairo had worked out with Granny Felyne—[Plan A for Kagaya Ubuyashiki]—Naofumi got to work.
Kagaya was already at death's door due to his illness and the recent trauma. Amane watched as the towering Naofumi unceremoniously shoved two pills into Kagaya's mouth, then poured a green potion in after them.
"Detox Fruit and Ancient Potion—don't die on us. We still need your help," Naofumi muttered.
And just then—Kagaya felt a mysterious strength surge within him.
The disease that had tormented him for twenty years began to fade. Even…
Light returned to his eyes. Though he was staring into the eerie gloom of the Infinity Castle, he could now clearly see the youth who had saved him.
"Thank you, and your comrades as well," Kagaya said softly. He had already heard unfamiliar voices from within the Prison Shield. "You… who exactly are you?"
"We are hunters." Naofumi thought a moment before answering. "Hunters who came to slay the monsters that devastate the balance of nature."
"We've come… to hunt Muzan."
——————————————
"WE ARE THE SOVEREIGNS OF MONSTER HUNTER!!!!"
Kairo Retsu stood proudly before Tanjiro Kamado and Giyu Tomioka, declaring with noble fervor, "We're nothing like those filthy, vile demons!!!"
"..."
Tomioka remained silent, katana raised warily.
He had seen them fall from the sky with his own eyes… then regenerate their bodies like demons.
Whether they were hiding their true nature or were some unknown variant, he couldn't lower his guard.
"Tomioka-san, I don't smell that kind of foul demon scent from him," Tanjiro said cautiously. "But there is a strange scent I've never encountered before… some kind of beast-like smell."
"Oh! You can smell that? It must be the equipment made from monster materials!" Kairo beamed. "As expected of Demon Slayer's main character… But anyway, let's cut the banter."
"We're hunters from another world, summoned on a quest to slay Muzan," Kairo said flatly. "And while on that quest, we've decided to save as many of you as we can."
"Our time is short," Kairo said quickly. "If we don't act now, Shinobu Kocho will die at the hands of Upper Rank Two. You'll encounter Upper Rank Three yourselves."
"Muichiro Tokito, Gyomei Himejima, the Shinazugawa brothers will face Upper Rank One. Obanai Iguro and Mitsuri Kanroji will fight the new Upper Rank Four. Zenitsu Agatsuma will face the new Upper Rank Six."
"It's not just the Pillars! All Demon Slayer Corps members are being pulled into the Infinity Castle!" Kairo pressed on. "There will be countless casualties—we must act now!"
"What are you even talking about…" Giyu started to protest—but Tanjiro interrupted him, sniffing deeply.
"Tomioka-san… there's no trace of lies in his scent!" Tanjiro said with some difficulty. "What he's saying might be true."
"If you're willing to cooperate, that would be ideal," Kairo said as his Monster Hunter system panel popped up. After thinking for a moment, he selected [Share View].
Tanjiro and Giyu could now see the floating interface in front of them.
Voices began to come through the party communication channel—on open speaker mode, audible to both of them.
Naofumi Iwatani: "I've secured the Ubuyashiki family. We can't move quickly, so I'll stay here and protect them. Also, Kagaya Ubuyashiki wants to speak with you."
Kazuma Satou (panicked): "I've got Tamayo! I stole her head from Muzan! I'm using Stealth to run through the castle!"
Joseph Joestar: "I got flung off somewhere on my own. Looking for the rest of the Corps!"
"Master!" Giyu lunged toward Kairo. "Master Ubuyashiki… is safe!?"
"This voice… Giyu?" Kagaya's calm voice came through the panel. "Don't worry. I'm… doing well."
"Mr. Kairo," Kagaya addressed him directly. "I heard from Mr. Naofumi that you're the Grand Master of your group. You descended from the sky to slay Muzan and saved us in the process."
"Yes. But let me clarify one thing—we're saving lives not because we seek compensation or to manipulate the Demon Slayer Corps."
Kairo spoke bluntly. "We're not here for flowery speeches! We are [Monster Hunters]! Here to slay monsters! Work with us!"
"Use all available means!!! Hunt the monsters that defy nature!!!"
"That's our Monster Hunter code!!"