The next Sunday came. Giyu’s phone pinged.
Shuto Todokori, 5:47 PM- We’re at the cafe.
Giyu put his phone away and silently motioned to Sanemi. Sanemi returned the gesture, changing the way he was leading Pochi. They saw three kids sitting at a table at the cafe. Shoto, Katsuki, and another boy with curly green hair and a sprinkle of freckles.
“You have a dog! That’s adorable!” The new kid, presumably named Izuku, exclaimed.
Giyu and Sanemi stiffened for a moment. Sanemi slapped his free hand to his face.
“Not this again…” Sanemi muttered, pulling up a chair.
“Is his voice also familiar?” Shoto asked, taking a bite from his mochi.
Giyu nodded. “If I had to describe it, he sounds like Yushiro, but with Tanjiro’s mannerisms.”
“Is there anyone else in your little group that’s gonna give us nostalgia?” Sanemi asked, annoyed.
“How the hell are we supposed to know?” Katsuki growled.
Giyu and Sanemi took a seat at the table, Pochi contently curling up by Sanemi’s legs. They quickly ordered the usual ohagi.
“So, you want to learn our techniques?” Giyu asked.
Shoto nodded. “Somehow, even though you don’t have strength enhancing Quirks, your physical abilities are far above average. We want to know what it is.”
Izuku vigorously nodded his head. Katsuki gave a single curt nod.
Sanemi and Giyu looked at each other, as if trying to communicate silently. “It’s a technique from the old Demon Slayer days,” Giyu began to explain. “It’s known as Total Concentration Breathing.”
“Total Concentration Breathing?” Izuku repeated, curious.
“As you can probably guess, it’s a breathing technique,” Sanemi said. “The key is drastically increasing your lung capacity to allow for maximum blood flow. It makes you stronger, faster, more durable. When paired with our swordsmanship, it puts us on par with demons.”
“Woah, that sounds really interesting,” Izuku said. “I mean, who could have guessed something as simple as proper breathing could have such a drastic effect on your physical form. I wonder if an equivalent of this has already been adapted. After all, it’s far too useful to be tossed aside, so maybe there are other Heroes who already know this at least under a different name-”
“He tends to ramble,” Katsuki explained, catching a glimpse of Sanemi and Giyu’s bewildered expressions.
“I thought you wanted to learn from us,” Sanemi grumbled.
“So you’ll teach us?” Shoto asked.
Giyu interlaced his fingers and rested his chin on his hands. “Yes, we’re willing to teach you.”
“If you’re willing to learn from a pair of vigilantes,” Sanemi sneered.
“Whatever,” Katsuki grumbled. “We’ve got our provisional licenses, so we are in the clear for any fights we get into under your watch.”
“We want whatever advantage we can get,” Shoto said, equally serious.
“We’re ready,” said Izuku.
“Very well, then,” Giyu said, moving to stand up. “We start now.”
“This is supposed to be your house?” Katsuki asked, looking unimpressed.
“You gotta problem?” Sanemi shot back, unlocking the door and letting Pochi inside. The shiba immediately waddled over to the closet. Sanemi opened the door and dug through the treat box, tossing a small cracker to her.
Izuku and Shoto took a second to take the place in. It was small, yet homely. The kitchen smelled vaguely of the sea; they must cook fish a lot. Almost every corner of the living room had some kind of pinwheel, all of them spinning from the light breeze coming from the open door. A small cage housing a rhinoceros beetle stood on a bookshelf.
“By the way, don’t you intern with Endevor?” Giyu asked as he locked the door. “Won’t he want to know where you are?”
“We’re done for the weekend,” Shoto explained. “We can come by when we won’t be missed. For now, that’s Sundays after the internship, or on our individual days.”
“Very well, let’s get started,” Sanemi said, walking into the kitchen to retrieve something. Giyu in the meantime motioned for Katsuki, Shoto, and Izuku to follow him into the backyard.
“In our past life, we did not have Quirks,” Giyu said. “The Demons had Blood Demon Arts, which are similar to modern day Quirks. So, we had to be skilled enough with traditional combat methods to fight against supernatural enemies.”
“Hence the swords?” Shoto asked.
Giyu nodded. “Our swords are made of a special iron called Nichirin. It’s a metal capable of absorbing sunlight, making it one of the few weapons capable of killing demons. Since these are the weapons we are most comfortable with, we continue to use them today.”
“Where’d you get them from, anyways?” Katsuki asked, kicking a stray pebble.
“Got them smelted on the black market,” Sanemi said, joining them. He was carrying four ceramic gourds and a pair of bokkens, balancing the items in the crooks of his arms. “What? We’re not exactly upstanding citizens,” he said in response to Izuku’s disapproving glance. He tossed one of the bokkens to Giyu, who caught it with practiced ease.
“Total Concentration Breathing is often used in companionship with swordplay, but they can be completely independent,” Giyu continued to explain. “If you’d like, we can teach you the basics, or we could just stick to Total Concentration Breathing.”
“What kind of swordsmanship do you practice?” Izuku asked innocently.
Sanemi sighed. “There’s a long history to the Demon Slayers’ swordplay. It started in the 1500s, with the original form, known as the Breath of the Sun. It was also the hardest to master, so many subforms were created.”
“The five main subforms were Flames, Stone, Thunder, Water, and Wind,” Giyu said.
“Water? Wind?” Shoto said as Izuku vigorously took notes.
“Is that why you call yourselves the Wind and Water Pillars?” Katsuki asked.
“Precisely. You sound like a smart cookie,” Sanemi said. “In any case, are you interested in the swordsmanship, or just the Breathing?”
“We can’t waste time,” Katsuki said with a growl. “Teach us the Breathing.”
Sanemi had a wild grin. “In that case, you’ll need these.” He held up the gourds in his arms.
“In the old days, there was a simple exercise you’d perform,” Giyu explained. Sanemi handed the final gourd to him before standing back. Giyu set his bokken against the wall. He held the gourd to his lips and blew into it. After a few moments, the gourd broke off into a shower of ceramic splinters.
Shoto, Katsuki, and Izuku watched with gaping mouths. “This was a simple demonstration, but both Sanemi and I are capable of breaking gourds the size of our bodies.”
“That’s incredible,” Izuku said in awe. “To do something like that, to break ceramic with just air… your lung capacity must be off the charts!”
“When are we going to be able to do that?!” Katsuki demanded to know.
“It varies,” Sanemi said with a shrug. “On average, most Demon Slayers trained for two to three years.”
“Two to three years?! We don’t have that much time!”
“We never said this was going to be easy,” Sanemi said, cross. “I recall you saying you’ll do whatever it takes.”
“We will,” Shoto said, voice assured. “We look forward to training under you.”
The trio returned to campus well into the evening with puffy reddened cheeks. When Eraserhead asked why they were so late, Shoto said Endeavor took them on a longer patrol this time around. They excused themselves to their rooms, not missing the concerned looks of Denki, Eiiro, and Momo.
“We’ll have to come up with a better excuse next time,” Izuku said when they gathered secretly in his room. “It won’t take long for them to put things together if we’re not careful.”
“Bakugo and I won’t be getting back until Tuesday, so we’ll think of something by then,” Shoto said, already in bed.
“Total Concentration Breathing is hard, though,” Izuku muttered. “What do you think, Kacchan?”
“I’m gonna do it,” the blond seethed angrily. “I’m going to get it before either of you, and I’ll be better at it, too.”
“I guess all that’s left is to practice it until we can see them again,” Shoto said. “Hard to believe they do it constantly. I was out of breath after just five seconds.”
“I’m sure we will get the hang of it eventually!” Izuku said, optimistic as ever.
Only the All Might memorabilia served as a witness to their secret.
The next morning, they got up and trudged through morning classes. Denki, Eijiro, and Momo kept trying to catch their eyes.
“Should we tell them?” Izuku whispered to Katsuki while they waited for Present Mic to hand out assignments.
“Not a chance,” Katsuki whispered in return. “Even telling you was pushing the envelope.”
The bell for lunch rang. Eijiro and Denki wasted no time catching Katsuki outside the classroom door. “So what’s the deal with those Demon Slayers?” Denki asked. “You know, next parent visitation day is coming up, so I can get my book copy, then-”
“Just drop it, Sparky,” Katsuki said, glaring daggers. “Don’t even think about sticking your nose into this.”
Denki squeaked and jumped back. “Fine, fine,” he said, rubbing the back of his neck.
Eijiro looked concerned. “Don’t shut us out! We’re just worried.”
“Well, you’re worried over nothing. Just a pair of troublemaking vigilantes. That doesn’t concern us.”
“Hey, if you won’t talk to us, at least tell Mr. Aizawa,” Denki suggested. “He should know about this.”
In the meantime, Momo was busy questioning Shoto.
“Yaoyorozu, I know you mean well, but this vigilante business really isn’t something we should be messing with,” Shoto said. “It’s best to let the Pros handle it.”
Momo pursed her lips, knowing he was hiding something. Nonetheless, she dropped the subject.
The three boys managed to meet up after the day’s classes were over. They went to Shoto’s room, away from prying eyes and ears.
“Alright, we should set some boundaries,” Shoto spoke up first. “Should we tell anyone, and if so, who?”
“I vote no one,” Katsuki grumbled. “First off, it would be hard to explain. Second, even if we aren’t technically breaking the law, it will reflect badly on us if people find out we’re hanging out with vigilantes.”
“I get your point,” Izuku mumbled. “But, Endeavor and Mr. Aizawa aren’t stupid. They’ll figure things out eventually, and we’d probably get in more trouble for not coming clean sooner. Remember, Todoroki and I are pretty much on thin ice, me mostly.”
“My old man is definitely someone who cannot find out about this under any circumstances,” Shoto said. “He holds vigilantes and villains in the same league. And Shinazugawa hates him. Even on the off chance we get off scot free, those two would be in serious trouble, and I don’t want them to go through that.”
“That leaves Mr. Aizawa and the rest of the class,” Izuku offered.
“We can’t tell the others,” Katsuki protested. “It is bad enough that Sparky, Dumb Hair, and Ponytail have a vague idea of what’s going on. If they or someone else finds out the truth, it will spread like wildfire because some people can’t keep their mouths shut. We can’t let too many people find out.”
“So, what about Mr. Aizawa,” Shoto said. “I reckon he would be rational enough to keep this under wraps. And, based on the way he conducted our lessons and his status as an underground Hero, he is less antagonistic to vigilantes than most.”
“Still, I don’t think we should spill their entire story without their permission,” Izuku murmured. “They- they really do seem concerned with not being seen as crazy.”
“Well, that’s an easy fix,” Katsuki said, pulling out his phone. “We could just ask them.”
Katsuki Bakugo, 6:43 PM- Hey, we might need to tell someone about you.
They waited for a response. “Okay, let’s say they agree. How are we going to tell Mr. Aizawa?” Shoto asked. “We can’t just walk up to him and say ‘the Pillar vigilantes are reincarnations of Demon Slayers from over five hundred years ago.’”
Their phones vibrated.
Sanemi Shinazugawa, 6:45 PM- Seriously? The one thing we ask you not to do and you’re ready to break that rule again?
Giyu Tomioka, 6:45 PM- You’re testing our trust.
Shuto Todokori, 6:46 PM- We were thinking of Eraserhead, our homeroom teacher. We’re just worried he might figure things out on his own and that will be worse for everyone.
The chat went silent, Sanemi and Giyu clearly talking it over.
Giyu Tomioka, 6:49 PM- Alright. We have conditions, though. We must talk to him in person. Explain the basics that we met up with you and are in correspondence. Tell him we want to meet.
Sanemi Shinazugawa, 6:49 PM- And we are only telling him so that he knows we aren’t kidnapping you or something.
Izuku Midoriya, 6:50 PM- Alright. We can do just that.
Sanemi Shinazugawa, 6:50 PM- And don’t you dare mention anything about reincarnation.