The soft scent of wisteria drifted through the open window of the small study room. Outside, the violet petals swayed gently in the morning breeze, glowing beneath the sunlight.
Akira sat near the window, surrounded by books and scrolls, handwritten notes on demon biology, blood analysis, poisons, and treatment records. The entire desk was buried under ink-stained parchment.
For him, these documents felt a little primitive, but then again, this was the Taisho era. No computers, no microscopes. Just careful handwriting and detailed observation. Still, considering the time period, he had to admit… these records were impressively thorough.
Akira leaned back, stretching his shoulders. Just as he was about to reach for another book, a familiar voice echoed softly inside his mind, calm, curious, and teasing. "You've been studying these books for hours, brother. Have you learned anything good?"
"Well," Akira said, flipping another page, "the notes are good, but a bit primitive. They don't go into much detail about demon biology or physiology. I mean, it's not bad, just… not enough. I'll probably have to capture a few demons myself and run some tests to really know more about them."
He paused, then added, "But I did come to a few conclusions based on what I've read."
"And what's that?" Selena asked, her voice curious.
"They're not supernatural beings," Akira said simply. "At least, not entirely."
"Wasn't that obvious?" she replied with mild exasperation.
"I mean, this world does have supernatural elements," Akira continued, glancing toward the window. "Like people who can talk to ghosts, the generational curse of the Ubuyashiki family, and the Blood Demon Arts. Those things definitely make the world feel supernatural, right?"
"Yeah, those sound supernatural to me," Selena said.
Akira nodded slightly. "Right. Some parts of it are, but these demons themselves…they're closer to something else."
"Something else?"
Akira leaned forward, grinning. "They remind me of the Flood. You know, from Halo."
There was a moment of silence before Selena's voice shot back in disbelief. "Wait… those Flood!?"
"Yeah," Akira said, nodding. "Basically, Muzan's blood or his cells act like a Flood supercell. It invades human tissue, rewrites it, and turns the host into a colony of itself. Every demon is just… an extension of him."
"So… it's a hive mind?" Selena asked, her tone shifting from surprise to intrigue.
"Kinda," Akira said, resting his chin on his hand. "But not exactly. The ones infected by Muzan's cells keep their own will, but remember, Muzan can read their thoughts. So it's more like a weaker version of the Flood."
He leaned back slightly, his tone calm and analytical. "Honestly, it's closer to a super cancer."
"...Cancer?" Selena repeated softly, now uncertain.
"Yeah. Muzan himself is like a super cancer," Akira explained. "If we compare him to cancer, it actually makes sense, doesn't it?"
"How, though?" Selena asked, her voice now serious.
"I mean, cancer cells are basically immortal. They can divide endlessly and spread uncontrollably," Akira said, tapping his fingers on the desk. "They sound overpowered, but cancer also has weaknesses, just like Muzan has his weakness to sunlight."
"That's… a bit of a stretch," Selena said with a small sigh.
"Maybe," Akira said, smirking. "But it helps me understand what I'm dealing with, and it still fits, though."
"Alright then, genius," she said in a half-teasing tone. "So how are we supposed to beat this demon 'super cancer' of yours? You gonna use the Halo rings?"
Akira blinked, thinking for a moment. "...That's not actually a bad idea, you know."
"I was joking, brother!" Selena exclaimed, her voice rising in disbelief. "Do you realize if you used those, you'd wipe out basically everything in this world!?"
"Oh. Right," Akira said casually. "That too."
He leaned forward with a thoughtful look. "Still, I do have some good ideas on how to kill all demons, though."
"Oh no… I don't like where this is going," Selena said warily, her tone filled with suspicion. "Knowing you, whatever comes next is going to be ridiculous. Let's hear it."
Akira crossed his arms with a grin. "My first idea is to make huge satellite mirrors in the sky. That way, when night comes, we can reflect sunlight across the land. Demons that come out to feed would burn instantly. If we can keep them up all the time, there'll be sunlight twenty-four seven and eventually, all demons would starve to death."
There was a pause.
Then Selena sighed, her voice echoing in his mind like an exasperated older sister. "Think of something you could actually do, brother. We're in the Taisho era, for God's sake!"
Akira said in a complaining voice. "Hey, the Russians will do it in a few years, right? Why can't I?"
"They did it in the 1990s, brother! That's eighty years from now! Where are you going to get the time, the manpower, or, you know, space technology!?" Selena said in an exasperated voice.
Akira tilted his head. "Fair point."
He leaned back slightly and said, "Okay, next idea, make a virus that selectively targets Muzan's cells and release it into the wild."
There was a long, stunned silence.
Then Selena's voice burst into his head, half scolding, half horrified. "Are you seriously copying the Blade Trinity ending right now!?"
"Hey, that worked, didn't it?" Akira said defensively.
"Yeah, in a movie! You do remember this is the Taisho era, right? There's no such thing as genetic engineering! And if you somehow made a virus, what if it mutated? You could accidentally create something even worse!" she said.
Akira sighed, tapping his pen against the desk. "Yeah, yeah, I guess you're right…"
He leaned forward with a small smirk. "But I do have one more cool plan."
"...Why do I feel like I'm going to regret asking?" Selena said cautiously. "Fine. What is it?"
Akira smiled. "It's called The Great Food Poisoning."
There was silence again.
Then Selena's voice exploded with disbelief. "WHAT!?"
Akira chuckled and began explaining, gesturing with his hands even though she wasn't physically there. "Think about it. We create a poison that's deadly to demons but harmless to humans, and spread it through the human food or water supply. Then, when demons eat humans, they die of food poisoning. Simple, efficient, and poetic justice."
Selena was silent for a moment, too silent. Then she finally spoke, her tone full of moral horror. "That's ethically wrong on so many levels! And it wouldn't even work! What if the demons built resistance to it? And how are you going to poison all of Japan, brother!?"
Akira waved a hand lazily. "Relax, it's just a thought experiment. It's fun to think about, right?"
"You call that fun?" Selena said in disbelief. "Please, just once, think of a normal way to kill them!"
Akira shrugged. "Alright, fine. The most practical way would be to poison Muzan himself. We'll need to capture him first, though… and figure out how to deal with his army."
"That's more reasonable," Selena said. "Still, if you became as strong as Yoriichi, you could just kill him outright."
Akira smiled faintly, eyes glinting with quiet determination. "Maybe. I'll try my best. I'm already working on it, actually."
"Wait, so that's why you wanted to observe Tanjiro and the others?" she asked.
"We can just call them the Kamaboko Squad," Akira said casually. "And yeah. I've already studied all the Hashira's breathing styles. What's left are Thunder, Beast, Flower, and Sun. I just need to get closer to them. Learn directly."
He leaned back, stretching again. "Oh, speaking of which, how's Erika doing?"
"She's training fine. See for yourself." Selena's tone sharpened to something like pride as she sent a clip through the Star Chats.
Akira tapped the play icon, and immediately, the song 'Gonna Fly Now' from Rocky started playing.
On-screen, Erika was shown stretching alongside Mitsuri, then sprinting uphill while dragging heavy logs tied to her ribbons. Then she balanced on one leg atop a wooden pole while carrying two massive stones, then lifted boulders like dumbbells. The montage ended with her shattering a wooden dummy with a single punch.
Akira nodded approvingly. "She's doing well. More athletic than I thought."
"Of course she is," Selena said softly. "She trained for years so she wouldn't be a burden to you. You always told her she should be 'a normal human' and that she should fight."
Akira's grin slipped. "Was that a shot at me?"
"Yes." Selena's reply was a dry, brotherly jab. "And you need to realize what you said hurt her. You should apologize."
Akira leaned back with a sigh. "I said what was good for her. She's a normal girl, remember when she was always afraid to fight and didn't want to learn magic."
"She's not that 'normal girl' anymore, brother. She changed the day you almost died. She trained harder than you can imagine, and your words made her sad." Selena's voice lost its teasing edge and grew serious.
Akira sighed, resting his head in his hand. "I just don't want her to get hurt because of me. This Star Chase journey… It's dangerous. Traveling through worlds, fighting, training, sure, it sounds cool, but it's not exactly a safe life."
"Do you really think she didn't know that?" Selena's tone sharpened into mild reproach. "She made up her mind. You're the indecisive one here."
Akira sighed, "Fine. As I promised already, I won't say that again. But how do I even talk to her? She's been avoiding me since last night."
"She's just embarrassed," Selena supplied, softer now.
"I know that," Akira said. "But I've never dealt with something like this before. What should I do?"
Silence stretched. Then the familiar, mischievous glint returned to Selena's mental voice.
"Hehe, I may have an idea…"