One Piece: With Sign-in System

"Go after... Muzan Kibutsuji?"

Shinobu was utterly stunned by Ron's words, staring at him as if she'd misheard.

"Yes," Ron replied calmly. "A full-scale war between the Demon Slayer Corps and the Twelve Kizuki is about to begin."

As he stood up and stretched lazily, his tone remained light, as if they were discussing the weather.

He glanced at Shinobu and smiled. "You want revenge on that Ice Demon too, don't you?"

Shinobu's violet eyes contracted sharply.

"You're only one step away from completely entering the Transparent World. Training might get you there eventually, but in a battle between life and death? That's when breakthroughs happen."

Ron reached for the ancient blade resting beside him and fastened it at his waist. As he walked past Shinobu, he added casually, "Of course, I'm not saying we're heading straight to Muzan today. It'll take about ten days or so. After all, none of you have awakened your Demon Slayer Marks or even turned your blades crimson yet. At your current level, you'd be hopeless against the Upper Ranks."

He stopped and looked back at her with a grin.

"That's why—it's time for everyone to undergo special training."

…

After Shinobu passed on Ron's words to Kagaya Ubuyashiki, the leader of the Demon Slayer Corps wasted no time. He immediately summoned the seven Hashira who were currently stationed at headquarters—excluding Giyu Tomioka and Gyomei Himejima, who were still out on missions.

After a brief discussion, every present Hashira agreed without hesitation—Ron's special training was a rare chance they couldn't afford to miss.

And so—

On the third day after returning from the Mugen Train incident, several individuals were summoned to the Ubuyashiki estate by Gotou, the Kakushi in charge.

Tanjiro, Zenitsu, Inosuke, Kanao, and Genya Shinazugawa were all gathered at the front gate.

"What's this about?" Zenitsu asked nervously. "Don't tell me there's another mission already?"

"Mr. Gotou, do you know why we've been called here?" Tanjiro asked politely.

"No idea," Gotou replied flatly.

Zenitsu's face paled. "Seriously?! No way, I just made it back alive from that terrifying train! I already fought a Twelve Kizuki! My wounds haven't even fully healed yet! I really don't want to deal with demons again!"

Inosuke groaned. "You're such a whiner! You didn't even get seriously hurt!"

"It's not physical injuries! It's psychological trauma! Something your thick skull clearly doesn't understand!" Zenitsu snapped back. "Besides—"

"Shut up, already. You're giving me a headache."

The voice came from Genya, whose body and face still bore the fresh marks of recent battles. His tone was annoyed and sharp.

"S-sorry!!" Zenitsu immediately stiffened in fear.

Tanjiro glanced at Genya thoughtfully.

That guy… wasn't he the aggressive one from the Final Selection on Mount Fujikasane?

His name was… Genya Shinazugawa, right?

His surname sounded a lot like the Wind Hashira's. Were they brothers?

Tanjiro couldn't help but wonder.

Kanao, on the other hand, walked silently with her usual soft smile, her expression unreadable as always.

Soon, they arrived at the secluded and heavily guarded Ubuyashiki estate.

Inside the courtyard, several imposing figures were already waiting.

Shinobu Kocho.

Kyojuro Rengoku.

Tengen Uzui.

Obanai Iguro.

Muichiro Tokito.

Sanemi Shinazugawa.

Mitsuri Kanroji.

"The Hashira…!"

Zenitsu gasped, his eyes widening. "So many of them together!"

"You're finally here. Took you long enough," Sanemi said coldly, arms crossed as he looked at them.

His gaze lingered on Genya for a brief moment, then turned away without a word.

Genya didn't even glance in his direction.

"Yo, Tanjiro."

With a hearty laugh, Kyojuro Rengoku waved toward Tanjiro, his booming voice echoing across the courtyard.

"Rengoku-san!"

Tanjiro grinned and waved back, clearly happy to see him.

Zenitsu and Inosuke immediately sidled up next to Tanjiro, their curiosity piqued.

"Tanjiro, who's that?" Zenitsu whispered.

"That's Rengoku Kyojuro—the Flame Hashira. He's a really kind person. He's looked after me and even told me to call him 'big brother.'" Tanjiro replied with a cheerful smile.

Zenitsu's eyes bulged with jealousy. "You—! Since when did you get so close to the Flame Hashira?! You've been secretly clinging to his leg this whole time?!"

Tanjiro tilted his head innocently. "Maybe the time we came here to report after the Mugen Train mission? You were still asleep back then, Zenitsu."

Zenitsu opened his mouth to protest again, but before he could, Mitsuri Kanroji walked up to them with a bright smile.

"You two must be Tanjiro's friends—Zenitsu and Inosuke, right? I've heard all about you from him. To think you three stood against a member of the Twelve Kizuki together… that's truly amazing!"

Her words, sweet as honey, paired with her soft, lovely features, made Zenitsu and Inosuke freeze for a second. Then their faces bloomed into expressions of sheer joy.

"Tanjiro, I take it all back! I'm sorry for doubting you earlier. You really are my best friend in the whole world!" Zenitsu gushed, clearly overwhelmed by the attention from such a cute girl.

Inosuke, on the other hand, just looked proud. He didn't really care who was talking—he was just happy to be praised.

"Huh?"

Tanjiro blinked, tilting his head, completely lost on what had just happened. But he didn't dwell on it. Turning to Shinobu, he asked curiously, "Miss Shinobu, why did you call us here today? Is there another mission?"

Zenitsu and Inosuke quickly focused up again, also looking at Shinobu with curiosity.

With her signature soft smile still in place, Shinobu replied gently, "You'll find out soon enough."

The three exchanged puzzled glances.

Moments later, a calm and clear voice rang out.

"Looks like everyone's here."

Everyone turned.

A tall, striking figure had appeared out of thin air in front of them.

"Mr. Ron?"

Tanjiro, Zenitsu, and Inosuke all stared in astonishment.

Even Genya's eyes widened in surprise and confusion when he saw the man.

So this is the one Master Himejima spoke about…

He had never seen Ron in person, but Genya had heard about him from his mentor, Gyomei Himejima. Still, this was not the appearance he expected.

Aside from his impressive height, Ron looked more like the polished heir of some noble family. There wasn't even the slightest air of hostility or power around him—at least on the surface.

But Genya wasn't foolish enough to underestimate him.

This was the man who had utterly defeated his own older brother—someone known for being borderline uncontrollable—and appeared without a sound. The man the other Hashira respected. The man his mighty mentor had admitted he couldn't defeat.

There was no way someone like that could be weak.

No, it had to be the opposite. He was so powerful that Genya couldn't even sense his energy.

Clenching his fists, Genya narrowed his eyes, locking them onto Ron's calm figure.

This guy… is seriously terrifying.