"Can we actively enter the Infinity Castle?"
The Flame Hashira asked, full of spirit.
Gusion shook his head. "Unless Muzan or whoever controls the castle opens the door, we can't get in. It's also hard to find."
He knew the Infinity Castle was based on the Edo-period castle keep, and in the original story, the Serpent and Wind Hashira once encountered many demons there and caught a glimpse of its interior.
But with the castle under Nakime's control, it could move anywhere in the country, opening portals at any location. Muzan's preferred way to gather the Twelve Kizuki was to have Nakime open a door and bring them all in.
After each meeting, the doors would open, and the Kizuki would return to wherever they'd been before—remarkably convenient.
Honestly, such spatial ability, in Gusion's eyes, already surpassed this world's expected difficulty. But the reality was that Muzan really had such a handy castle, and they had to find a way to deal with it.
"In that case, perhaps we can lure the snake out of its hole,"
the Serpent Hashira analyzed.
"Do we need bait?"
Shinobu Kocho mused. "Muzan likely wants to kill the Hashira as well. If we're alone outside, will he open the castle's door and send demons to ambush us?"
The Hashira's movements were usually secret, known only to the highest ranks of the Corps. Since demons couldn't gather intel during the day, unless the Hashira sought out the demons themselves, it was hard for demons to hunt the Hashira.
But if they deliberately exposed themselves, Upper Moons would likely come.
"It's not that easy. Forgive me for saying so, but among those present, except for Himejima, the rest of you—if your whereabouts are exposed, it's a death sentence."
Gusion said bluntly, "And to kill any of you, the remaining Upper Moons Four could do it. Muzan wouldn't even need to open the Infinity Castle."
He wasn't making this up. Even if the Hashira could possibly awaken their Marks in battle, aside from the Stone Hashira, the rest couldn't defeat Upper Moon Four one-on-one.
Especially now, with even stronger explorers on Muzan's side—they wouldn't let Upper Four act alone.
"You're too arrogant!"
The already dissatisfied Wind Hashira stood up in anger. "You think only you can kill Upper Moons…"
He stopped mid-sentence.
Because, as a violent wind swept by, Gusion's hand—shaped like a knife—rested on the back of his neck. Gusion was now behind him, and the Wind Hashira hadn't even seen him move.
"If I wanted to kill you, you'd already be dead."
Gusion withdrew his hand, his voice flat. "I grew up on stories of the Hashira, but to be honest, most of you are too weak."
Only now did the Wind Hashira recover. In just an instant, his back was soaked with cold sweat. When he looked at Gusion again, he saw him with a new sense of awe.
In terms of raw power, he'd only respected the Stone Hashira before, but now he'd seen another monstrous figure. If nothing else, Gusion's speed far exceeded his own as the Wind Hashira.
"I believe everyone now understands the reality,"
Gusion said as he stepped aside. "I could easily kill everyone here except for Himejima. But even for me, killing the remaining Upper Moons is no simple task. The first four are much stronger than the two I've already killed."
"Thunder Hashira, what are you trying to say? Is it just to show how strong you are and how weak we are?"
The Serpent Hashira's voice was low and unreadable.
Under the stares of all the Hashira, Gusion nodded calmly. "Exactly. That's the premise. Only if you understand it can I continue."
No one liked being called weak, but the Hashira weren't ordinary people. Their mentality was strong; power wasn't their only concern. They all had hearts devoted to slaying demons and saving others.
So none of them interrupted, waiting for Gusion to continue.
"Next is today's third topic—something the Oyakata-sama and I discussed and concluded together."
Gusion said, "For the next two months, all Hashira will stop demon-slaying missions and undergo intensive special training."
He'd arrived at the Oyakata-sama's mansion last night, and after a long talk, explained the importance of Miss Tamayo and the current situation.
Once the Oyakata-sama understood the true strength of the Upper Moons and the fact that Muzan's side had expanded, he immediately saw that the offensive and defensive positions had reversed.
The Hashira were no longer the hunters but had become the hunted by the Twelve Kizuki.
With the enemy now having a strong intelligence network, letting the Hashira scatter and act alone would be suicide.
Therefore, after much discussion, they decided that except for Gusion and Himejima, all Hashira would undergo training.
Well, that was the official line. The real reason was to protect them, to keep them from being hunted before the final battle.
Of course, if they grew stronger during the training, so much the better. That would give them a greater chance in the final battle.
As for outside operations, those wouldn't stop completely. Gusion and Himejima would handle teaching and training, and step out if particularly powerful demons appeared.
"Special training—now that sounds exciting!"
The Flame Hashira said enthusiastically. "It'll make us stronger, and we can save even more people, right?"
Gusion nodded. "The Oyakata-sama will arrange a hidden location for training. The Demon Slayer Corps will operate as usual; powerful demons will be handled by Himejima and me."
"As usual? The other Corps members won't join the special training?"
The Serpent Hashira asked.
"Each Hashira can pick a few favored subordinates or Tsuguko to join. The rest will continue with normal missions. Too many people in training won't help."
Gusion said.
In the original, the entire Corps underwent training before the final battle, but Gusion thought that was overkill. Most Corps members were just ordinary people without talent; even after elite training, they wouldn't improve much, so it was better for them to keep doing their jobs.
And in fact, being ordinary made them safer—hundreds of people scattered across the country were a much smaller target. The explorers wouldn't bother to hunt them down.
And regular Corps members could kill weaker demons and protect people too.
On this land, both demons and demon slayers were rare. No matter how strong the Hashira were, most of the time, their work was the same as any Corps member—hearing of trouble, then heading out to kill demons.
It was just that some demons were too tough for ordinary members, so the Hashira had to step in.
"That makes sense. But without us on missions, more people will surely suffer at the demons' hands. How pitiful."
The Stone Hashira wept but agreed with the plan.
"Training is fine, but that still doesn't solve the Muzan problem. How do we get into the Infinity Castle?"
The Serpent Hashira voiced his doubt.
"With the bait you mentioned."
Gusion answered, "But it can't just be a weak bait. It has to be something important enough to draw Muzan himself, and ideally able to fight back and stall for time, so all the Hashira can rush in together."
"We're not even qualified to be bait, are we?"
The Wind Hashira said bitterly.
Gusion nodded. "Given mobility, I'm currently the best bait."
Actually, he and the Oyakata-sama had devised two plans for bait, and the plan with Gusion as bait wasn't very reliable.
Because even if he were ambushed outside, Muzan might not open the Infinity Castle. Even if he did, with the castle's properties, he could just pull Gusion in instantly, leaving no time for the others to join.
So the best bait had to be someone so important that Muzan would act personally—the Oyakata-sama himself.
If Muzan was forced to attack the Oyakata-sama, then under pressure he'd open the castle, allowing everyone to enter together.
Of course, since this plan would almost certainly cost the Oyakata-sama's life, most Hashira would object. Gusion himself didn't like it either.
He'd already joined this world on the Demon Slayer side. If they had to sacrifice the Oyakata-sama just to win, that would be a disgrace.
So Gusion had his own ideas about bait.
For now, the best they could do was get the Corps organized and start training the Hashira.
Gusion didn't expect the Hashira to offer overwhelming help in the final battle, but he didn't want to see these tragic warriors, who'd given their lives to slaying demons, die. They deserved a better ending.
And after saving the Sound Hashira, he'd received a hidden mission:
[Hidden Mission: Perfect Ending]
Mission: After killing Kibutsuji Muzan, ensure as many of the current nine Hashira survive as possible. Rewards depend on the number of survivors.
5 survivors: 3 free attribute points
6 survivors: 4 free attribute points
7 survivors: 5 free attribute points
8 survivors: 6 free attribute points
All survive: 10 free attribute points
Failure penalty: None
[]
The rewards were generous—if he achieved a perfect ending, he'd get 10 free points, equal to a full world's final tally.
So whether for personal reasons or the mission, Gusion wanted all nine Hashira to survive, apart from himself.
"One person as bait is too dangerous. When you go out, I'll go with you,"
Himejima suggested. He recognized Gusion's mobility but doubted he could handle several Upper Moons alone.
Besides, with both of them as bait, the target was bigger—Muzan might take the risk to act himself.
"I appreciate your offer, Himejima, but let's set that aside for now. Let's discuss special training."
Gusion smiled. "Since I proposed this to the Master, I naturally have a reliable way for everyone to get stronger."
At Gusion's words, all the Hashira were curious. Who didn't want to get stronger? Especially now, with Muzan found—each Hashira wanted to kill him.
Sensing their eagerness, the Oyakata-sama also spoke up.
"Gusion, don't keep them in suspense. Show them."
Gusion stopped talking. Under the Hashira's astonished gazes, his aura soared, and magical patterns appeared on his body.
"This is…!?"
Kyojuro Rengoku, the Flame Hashira, exclaimed. With deep family heritage, he recalled notes left by the first generation swordsmen. The strange patterns on Gusion's body reminded him of a power described there—"the Mark!?"
The other Hashira were drawn in by his words. Most of them were hearing it for the first time.
But whatever Gusion had displayed, they were deeply interested. All the Hashira could feel this wasn't Breathing Technique, but some other secret art—one that instantly boosted physical power!
If they could learn this, combined with Breathing, their strength would increase exponentially!
"Because I couldn't master Breathing for many years, I developed other ways to fight demons. I created this secret technique to maximize human potential."
Gusion said, "After using it, your strength, speed, and dynamic vision will improve dramatically. I call it 'Demon God.' Interested in learning?"
He was going to teach the Demon God technique to the nine Hashira. It had far fewer side effects than the Mark, could be accessed at will, and its power boost was at least as great.
Simply put, the Mark was a crude way to overdraw potential. Those who awakened it late paid a price—shorter life, and for swordsmen over 25, it meant death.
But Demon God was different. While individual boosts varied, its drawbacks were much less, and its boost to reaction speed was far above the Mark.
Overall, Demon God was like an upgraded version of the Mark—boosting strength, perception, and analysis in battle.
As for whether the Hashira could learn it, the answer was yes.
Gusion had created the technique himself and understood it deeply. While his teaching wasn't perfect, he could explain the principles clearly—and he'd once taught armed haki to Raian.
Demon God was even easier to learn than haki. The nine Hashira were all geniuses—someone like Muichiro Tokito became a Hashira just two months after picking up a sword. For him, learning Demon God would be a breeze.
Gusion was confident he could upgrade the Hashira in two months. When the final battle came, their chances would be much higher.