After an arduous journey and a lengthy meeting with Kagaya regarding the vaccine, Akira, Erika, and Shinobu were finally walking back to the Butterfly Mansion.
"Well, that went well," Akira said casually, stretching his arms.
Erika, clearly not amused, crossed her arms. "What went well?" Her tone carried mild irritation. "You mean using that vaccine on Demon Slayers went well?"
Akira shrugged. "It's just a decision that had to be made. They're not spreading it all across Japan, just to those who actively fight demons. And honestly, if someone's in a situation where they're about to be turned into a demon, they're probably dead either way."
Erika gave a sharp sigh. "But why would they want to administer it without telling the Demon Slayers what it really is?"
"Oyakata-sama must have his own thoughts," Shinobu said softly. "Besides, it would be better if the demons didn't know about the vaccine."
"Yep," Akira agreed, nodding. "Best to keep it under wraps."
Erika sighed in defeat. "Whatever…"
Soon, they reached the Butterfly Mansion. As they stepped through the gates, Aoi and the three little girls rushed to greet them.
"Shinobu-sama! Akira-san! Erika-san! Welcome home!" they chorused, bowing so fast they almost tripped.
"Welcome home!" Naho said brightly.
"We missed you!" Kiyo added.
And Sumi quickly followed, "Shinobu-sama, you have to listen to this! The Sound Hashira tried to kidnap us!"
"Wait…what!?" Shinobu's eyes widened.
Aoi, looking a bit flustered, added, "Uh… while you were gone, the Sound Hashira came here…"
"And what's this about kidnapping?" Shinobu demanded.
Kiyo quickly explained, "He said he needed help for a mission!"
Sumi jumped in, "He tried to take Aoi-chan too!"
"He did!" Aoi said, flustered. "He said, 'You two, come with me, I need women!' Then he picked me and Naho up and tried to take us to the Entertainment District!"
"Wait… what!?" Erika exclaimed.
Shinobu blinked in disbelief. "He did what?"
"In the end," Aoi continued, "Tanjiro-san, Zenitsu-san, and Inosuke stopped him. He took them to the Entertainment District instead."
Erika tilted her head, clearly confused. "Huh?"
Shinobu asked, "Why are they going to the Entertainment District again?"
"I heard it's about a mission," Aoi said. "I don't know all the details, though."
"Yeah, that makes sense," Akira said, hands in his pockets. "That place is perfect for a demon to hide and hunt. But why would he need those three, anyway?"
He asked that even though he knew exactly why, he had to create a situation where they could go to the Entertainment District.
Shinobu sighed. "I don't know, probably trying to find the demon by having them infiltrate the place. But I thought his wives usually do that kind of work."
"Wait, wives?" Erika asked, her eyes wide. "Wives? As in, plural?"
"Yes," Shinobu replied calmly. "He has three wives."
"Three!?" Erika shouted, completely shocked. "Is that even legal here!?"
"It's illegal," Shinobu smiled faintly. "But he's from a shinobi clan, so I don't think they care."
Akira grinned. "A shinobi, huh? That's actually kinda cool."
"When did they leave?" Shinobu asked.
"Yesterday," Aoi replied.
Shinobu smiled her usual gentle smile and said, "After they return, I'll have a talk with him about forcefully taking my subordinates."
But everyone could tell, behind that sweet smile, Shinobu was furious.
Aoi suddenly remembered something.
"Oh! Akira-san, the swordsmiths delivered your motorcycle and the sword you requested."
Akira's eyes immediately lit up. "Really!? Where is it!?"
"It's in the shed behind the house…" Aoi began, but before she could finish, Akira was already gone in a flash.
"I'm going to look!" he shouted, his voice echoing through the hall.
Erika sighed. "Honestly…" She followed him, and the rest of them trailed along too, mostly out of curiosity.
They all arrived at the small shed behind the Butterfly Mansion. Inside, Akira's eyes sparkled the moment he saw it, his bike. It looked completely brand new, spotless and polished as if freshly made.
"My bike!" Akira cheered, hugging it tightly. "I finally got it back! No more walking!"
Erika sighed. "It's just a bike, calm down. I didn't even know you liked them this much."
Akira said nothing, still clinging to the machine like a long-lost friend.
Selena's voice echoed telepathically in Erika's mind. "He is normally like this about vehicles, Erika-chan. He loves cool vehicles. Anything that looks awesome catches his interest. He just didn't show it much because he couldn't drive them before".
"Really?" Erika asked, looking at Akira.
"Yes," Selena replied. "Remember how he built hoverboards back then, even though he could already fly using magic?"
Erika thought for a moment and realised it was true.
Then she noticed a huge wooden box near the bike. "What's that?" she asked, pointing at it.
Aoi answered, "That's the weapon, the swordsmiths delivered it along with the bike."
Shinobu tilted her head. "What kind of sword is that big?"
"I don't know," Aoi said, a bit confused, "but the swordsmith who delivered it looked really angry for some reason. He said, 'What kind of monster needs this monster of a weapon?'"
Akira's attention snapped toward the box. "Oh! Is this my sword?"
Erika raised an eyebrow. "What kind of weapon did you even ask for?"
Akira grinned. "Hehe… you'll see."
He knelt down and slowly opened the massive box.
But when they saw what was inside, everyone's eyes widened in shock.
It was a sword, well, calling it a sword didn't feel quite right. The thing inside was massive, around seven feet tall, one and a half feet wide, and at least two to three inches thick.
Everyone stared in disbelief, wondering if such a weapon could even be wielded.
Erika, however, instantly recognized it. Her eyes widened. "Wait… that's…!"
It looked exactly like the weapon wielded by Guts from Berserk.
Akira turned to them proudly. "How's my new sword? Isn't it cool?"
"That's… a sword?" Shinobu muttered. "No, it's too big to be called a sword. Massive, thick, heavy, and far too rough. It's more like a heap of raw iron."
Akira's eyes gleamed as he excitedly repeated, "Exactly! This is cool!"
Erika sighed. "Why this? Do you even know how to use it?"
Then why get it!?" she exclaimed.
"I don't think anything else can handle my breathing style," Akira replied seriously.
"But can you even use it?" Erika asked, with an unbelievable expression.
"I can try," Akira said confidently. He gripped the handle with both hands and lifted it up with surprising ease. "See? I can use it just fine."
"Sure, you can lift it," Erika muttered, unimpressed. "But how are you going to fight a demon with it? The Upper Moons aren't exactly slow enough for you to swing that thing."
Akira chuckled. "Don't worry, I've got a plan for that. Look, there."
He pointed toward the box again. Inside, it lay two normal-looking katanas that nobody had noticed before because of the sheer size of the larger sword, which shocked them too much.
"When I fight an Upper Moon," Akira said confidently, "I'll use those."
Erika frowned. "But didn't you say they'll break after you use them?"
"Yeah," Akira nodded. "I can only use one strike with each. But as long as I can kill the demon in one hit, it's not a problem, right?"
"Then why did you even make this big sword?" Erika asked, exasperated.
"Because it looks cool, and it goes well with my armor!" He grinned and silently summoned his jet black armor, Eclipse, in a smooth wave of purple light. Then, striking a heroic pose with the enormous blade resting on his shoulder, he declared proudly, "Look! I look just like Guts, right? Right!?"
Erika could only sigh, while Shinobu said with a strained smile, "If the swordsmiths find out you made them forge this just for fun, they'll be very mad."
Akira laughed. "Well, only if they find out, right?"
Erika facepalmed. "So… are you actually going to train with it?"
"Huh? No," Akira said, setting the sword down. "I'll do that later. For now, I just want to take a good rest. It was an arduous journey, after all. I deserve a break."
Erika sighed again. "Not a bad idea."
"Are you not going to the Entertainment District?" Selena's voice echoed telepathically.
"I'll go later", Akira replied mentally. "They just left yesterday. It'll take them at least two days to reach the place, and the real fight won't start until after another three days. I'm tired, and I need time to rest and get used to this weapon. We can reach them faster anyway, by flying or on my bike. No problem".
A few hours later, after resting, Akira began swinging his new sword to practice.
Each swing cut through the air with a sharp whistle, creating gusts powerful enough to push back anyone standing too close.
Erika, who was sitting nearby with her arms crossed, watched in disbelief.
"I can't believe you're actually using that thing," she muttered.
Akira grinned, not stopping his swings. "Well, I am strong."
Then he paused for a moment, resting the massive blade against his shoulder. "Oh, by the way, since there are no dragons here for me to slay, I've decided to call this sword the Demon Slayer. What do you think?"
Erika rolled her eyes, then she sighed softly and said. "Well… it doesn't really look like Dragon Slayer anyway."
Unlike the Dragon Slayer from Berserk, Akira's sword, the Demon Slayer, was a Nichirin Blade. When Akira held it, it changed color, and now a purple line ran through its center, the same vivid shade as his eyes.
Erika tilted her head. "So… what are we going to do next?"
Akira planted the sword into the ground and stretched his shoulders. "We'll rest for a few days. Then, we'll start hunting the Upper Moons."
Erika blinked. "And how exactly are you going to find the Upper Moons?"
Akira smirked confidently. "Don't worry. Knowing us, trouble will find us first."
Just as Akira had predicted, a few days later, a message arrived.
Shinobu gathered Akira and Erika in the Butterfly Mansion's hall. "A message just came from the Sound Hashira," she said with a serious expression. "Zenitsu-kun has disappeared."
"What!?" Erika gasped. "How!?"
"They were infiltrating the Entertainment District to locate a demon hiding there," Shinobu explained. "But suddenly, Zenitsu vanished. Apparently, Uzui-san's wives have also gone missing. So he sent a request for reinforcements."
She looked at the two of them and said, "You're the ones who can get there the fastest. Can you go?"
Akira crossed his arms and nodded firmly. "Sure. We also want to find the Upper Moons anyway. Who knows, we might find one there, too. In fact…" He smirked. "We'll leave right now. No time to lose."
"Wait, right now?" Erika said in surprise.
"Yes," Akira replied, getting up. "So many lives are in danger. We have to reach there as soon as possible."
Erika sighed. "Are we at least taking the bike?"
"As much as I want to," Akira said regretfully, "no. We can't reach it fast enough with it. We're going to fly. If we fly, we can reach there before sunset."
"But it's still morning," Erika said. "I can't fly in front of everyone."
Akira turned back with a grin. "Well, you can just turn us invisible, right?"
"I can," Erika admitted, "but I can't maintain it for long."
Akira smiled knowingly. "Vampires regain strength after drinking blood, right? You can just drink mine mid-flight to keep it up. It'll count as training for you, too. What do you say?"
Erika sighed deeply. "You've already decided, haven't you?"
"Yep," Akira said cheerfully.
"…Fine," she said at last. "I'm worried about everyone, too, so let's do this."
"Cool." Akira turned toward Shinobu. "Okay then, Shinobu-san, we're leaving."
"Thank you," Shinobu replied softly.
But before she could say another word, Akira had already grabbed Erika by the hand and was dragging her toward the garden.
Good thing they were already packed and ready; there was no time to waste.
Moments later, the two of them lifted off into the sky, heading straight for the Entertainment District, where Upper Moon Six awaited their arrival.