For the next two weeks, Tanjiro and Nezuko did nothing but rest. Aoi was in charge of treating them, and she forbade them from so much as taking a walk outside.

“Your rehabilitation training will start soon, but it will be useless if your muscles aren’t rested properly first,” she told them.

Most of their time was spent either in the room they shared with Zenitsu or Inosuke or in Genya’s room. Both wound up being emotionally draining environments.

Zenitsu kept wailing about how disgusting the medicine was, only gathering up the courage to drink it with Nezuko’s intervention. Still, he made horrid gagging faces that made Nezuko pity him even more. After Inosuke woke up, he dogpiled them with questions about Genya and how the trial went. He yelled and ranted until his voice went hoarse, which caused him to sulk. As much as Tanjiro and Nezuko appreciated that they were safe, the constant loud room would get overbearing.

With Genya, the ambience was the exact opposite. He had stopped crying, but he remained in his small childlike state, his clothes now loose and elongated sleeves hanging over his hands. He didn’t talk aside from murmurs and he spent most of his time sleeping, forsaking the box for the comfortable bed. He always had either his muzzle or the gun nearby, but he refused to let anyone near the damaged drawing. When his siblings were present, he would insist that one of them would hold him.

“He’s… probably just desperate for that nii-chan affection,” Tanjiro said as Genya dozed in his arms. “After Shinazugawa did… that, he-” His voice died off, drowned by sorrow. Nezuko didn’t reply, instead opting to glare at the floor. Her visible, fractured hatred for Sanemi hadn’t diminished in the slightest.

The only other event of note was Tanjiro meeting with Murata and Ozaki. Both of Ozaki’s arms were heavily wound and bandaged, while Murata seemed relatively unscatched.

“How are you doing, Ozaki-san?” Tanjiro asked. “Are your arms feeling better?”

Ozaki waved them stiffly. “Could be better. Aoi-chan said it will probably take me a few weeks before I can even go through rehabilitation training.”

She looked down, guilt lining her features. “Still, I- I don’t know if I even deserve this second chance. Controlled or not, I killed people. My blade was the reason my comrades died. I’ll never be able to live down the guilt.”

“You do deserve a second chance,” Tanjiro said firmly. “The very fact that it was against your will and you regret it is proof enough.” He gave her his best reassuring smile. “Give meaning to the lives of your comrades. You can’t give up.”

She chuckled, a distinct lack of humor behind the laugh. “You really have a way with words, kid.”

“By the way, Tanjiro, how’s Genya?” Murata asked. “We heard about the trial, and we know how scary-” he paused as Shinobu passed by the room they were in, now dropping his voice down to a whisper, “- how scary the Pillars can be. I had to go to the meeting to give a more detailed report on the events of the mission and it was a nightmare!”

Tanjiro frowned, his expression being all they needed for an answer.

After two weeks, Shinobu did a preliminary check on the four of them, and deemed all of them except Zenitsu fit to begin rehabilitation training.

“You three will be training with Aoi and Kanao,” Shinobu told them. “They’ll explain the rest.”

“Right, let’s get to work,” Aoi said. “The rehabilitation training consists of three parts. First, you will do stretches with Kiyo, Sumi, and Naho.” She directed their attention to the three younger girls and a few tatami mats.

“Next, reflex training with me and Kanao,” Aoi said, pointing to the table line with cups. “Your objective is to be the first to splash your opponent with medicine water, and block the opponent’s cups with your hands. Lastly, there’s full body training, again with me and Kanao. Basically, a game of tag.”

Nezuko nodded along, seemingly the first to get it. “I’ve been to the Butterfly Mansion a few times before, so I know the basis of how this all works.”

“Then let’s do our best!” Tanjiro proclaimed. “We’ll get better in no time!”

Despite Tanjiro’s words, progress was slow. Even though Aoi had less combat experience than them, she was a fierce opponent when compared to their weakened states, outmatching them on most occasions. Kanao outmatched them on all occasions. Even the flexibility training proved to be a harrowing feat, with the ever flexible Inosuke being reduced to blubbering tears by the stretches.

“Please tell me what’s going on?!” Zenitsu would wail when they returned haggard every evening for the next two weeks. “I’ll be joining soon! Probably after Kocho-san’s next checkup! Please! I need to be prepared!”

“It can’t be described in words,” Nezuko said, hiding under her blanket.

“Nezuko-chan!”

“I’m sick of losing,” Inosuke said under his breath, retreating under his blanket. His boar mask covered his face, but he was clearly exhausted. With the strings of defeat accompanying the girls of the Butterfly Mansion, he had lost his drive and motivation.

Tanjiro was sitting up in bed, clutching at his blanket. “Nezuko, we should go see Genya. He’s probably lonely.”

“You’re right.” Nezuko dragged herself out of bed. The two siblings waved goodbye to a worn out Inosuke and terrified Zenitsu and made their way down the hall. Tanjiro entered first, opening the door. The slight squeak of the hinges alerted Genya to their presence, causing him to jolt awake in bed. He let out a happy yell, running over to them.

Nezuko bent down, petting him on the head. “Still, this feels odd,” she murmured.

“It makes Genya happy, and that’s what matters right now,” Tanjiro said. He picked Genya up and carried him back to the bed. He let Genya rest his head in his lap as Nezuko sat down next to him.

“We still have a lot of work ahead of us,” Tanjiro said with a sigh. Genya looked up at him. “I didn’t get the Demon Moon’s blood, and now the cure might be set back.”

“You did what you could,” Nezuko assured him. “Getting stronger is what’s important right now, so that we’ll be able to do it next time we meet a Demon Moon.”

Tanjiro nodded. “Oyakata-sama said that’s how we’ll prove ourselves to everyone, and we need it for the cure, anyway.”

“By the way, what happened with your fight against Lower Moon Five?” Nezuko asked. “You looked very badly beat up when I saw you in the forest.”

Tanjiro paused. “I used the Hinokami Kagura.”

“The dance Father taught you and Genya?”

Tanjiro nodded. Nezuko wore a puzzled expression. “So… it’s actually a Breathing technique?” Genya tilted his head.

“Seems like it,” Tanjiro replied. “Now that I think about it, it might be connected to why Muzan wanted to kill me.”

“What makes you say that?”

“Father told me to make sure that these hanafuda earrings and the dance get passed down the family line no matter what,” Tanjiro said, pointing to his ears. “And, if I remember correctly, one of the demons in Asakusa called me the ‘hanafuda earring boy.’ Seems like a very strange feature to point out.”

“That does make sense,” Nezuko nodded. “So, you think that our family has some sort of connection to old Breathing techniques? And Muzan is afraid of it?”

“Then the Hinokami Kagura must be especially strong,” Tanjiro determined. “If I can master how to use it in combat-”

“Teach me,” Nezuko said. Tanjiro looked at her. “Teach me the Hinokami Kagura. I know the basics from watching Father perform it every year, but I want to learn it in full. I want to help as much as I can.”

Tanjiro seemed taken aback by her declaration. “I mean, if you’re that driven, then I will, but- I’m the eldest son, so it’s my responsibility-”

“Well, I’m the eldest daughter,” Nezuko insisted. “And I want to help.”

Genya wiggled again, shaking his head vigorously. As he shook out his limbs, they extended and elongated. After a few seconds, he had returned to his usual, tall height and sat up.

“Genya! You’re back!” Tanjiro exclaimed, wrapping him in a tight hug.

“I’m… the eldest son,” Genya murmured. His voice was quiet, subdued. “It’s… my responsibility.”

“We can all shoulder the burden together,” Tanjiro said.

“That’s your problem, Tanjiro,” Genya said. “When you… are shouldering the burden, you do it on your own. But, when it’s someone else… you say we’ll do it together. You’re… too kind, Tanjiro.”

Tanjiro looked away, not having a response.

“Sorry… I haven’t been a good big brother lately,” Genya said. “I’ve been…”

“It’s okay,” Nezuko said. “You’ve been in pain. We understand.”

“I… want to help,” Genya murmured. “I want to help you find the cure, so that I can be human again. So that ‘Nemi will be my brother again.”

His words made Nezuko’s heart twist. “Don’t talk like that, nii-chan,” she said. “You’re better than that, you don’t need to be a human to be worthy of love. He doesn’t deser-”

“Please don’t talk about him like that,” Genya interrupted, looking away. “‘Nemi’s had enough of people talking bad about him.”

He froze, his bottom lip trembling. He shivered. “I- remember now. Why he’s mad at me. Our mom- was a demon. He killed her to protect me. I called him a murderer.”

Hearing Genya recount the story Tanjiro learned years ago hurt just as much as the first time.

“I- I can smell the love he has for you,” Tanjiro said. Nezuko looked at him in surprise, even though Tanjiro’s nose had never been wrong. “He loves you so much, Genya. But still, I can’t imagine anyone doing that to their little brother.”

“I know,” Genya mumbled. He twiddled his fingers, eyes downcast. “It hurt, but- I understand. And… I can’t blame him. Not for anything anymore.”

Nezuko and Tanjiro stayed silent. Every word caused their hearts to ache.

“I want- I want us to be brothers again,” Genya continued. “I want it more than anything in the world. That’s why I didn’t try to bite him. Even though he smelled of watermelon.”

“He smelled like… watermelon?” Nezuko repeated.

Genya curled into himself, realizing the extent of his confession. “His blood did. It smelled like sweet watermelon. And ohagi. And sake. And I missed watermelon so much… So when the dr-drawing-” he paused and whimpered, “when it got damaged, it was all I could focus on. That, and constantly saying to myself ‘he’s your brother, don’t bite him’ stopped me from attacking him.”

He paused and smiled to himself, his fangs poking out from the corners of his mouth. “The idea… that we could be brothers again, it keeps me going.”

Tanjiro and Nezuko exchanged glances. Even through his pain, Genya believed in his big brother. Neither of them was sure they could extend that same courtesy to Sanemi. But it wasn’t something they were going to tell Genya, who’s spirits only now started to rise again.

“Alright,” Tanjiro said. “Our goal is still the same then. Find a cure and turn you back into a human, so that you can find your brother once again.”

“And I want to help,” Genya said. His voice, while still soft, gained an edge of determination. “No more turning away, no more running. I’ll face everything head on with you.”

Tanjiro and Nezuko both nodded.

“Did you mean it? What you said in the trial? That I can fight as a Demon Slayer?”

Tanjiro nodded again. “It’s just like before-”

“No, not just like before,” Genya interrupted. “Demons can’t kill other demons. A demon can’t be a Demon Slayer. Unless they have-”

“A Nichirin blade?” Nezuko asked, coming to the realization. “But, with a sword, it would be easy to hurt yourself. And we don’t want that.”

Genya fell silent, thinking. “Maybe… it doesn’t have to be a sword.”

He got up and walked over to his box, rummaging through it. “Here,” he pulled out his gun.

“Oh, I see!” Tanjiro exclaimed. “You want to see if you can get Nichirin bullets!”

Genya nodded and smiled. “I… want to be able to help. However I can. And I’m pretty good with this, and there’s a lesser chance of me hurting myself with it.”

“I’m supposed to be getting my sword reforged soon,” Tanjiro said. “I can send a crow and ask about that.” Genya nodded in agreement.

“There’s also your Blood Demon Art,” Tanjiro said. “During the fight against Lower Moon Five, you used his Blood Demon Art, didn’t you? I saw multiple threads and he wasn’t controlling all of them.”

Genya nodded. “And also, the Blood Demon Art of the arrow demon from uh-” he paused, not remembering the name.

“Asakusa?”

“Right. I used his Blood Demon Art to push the demon into your blade so that you could cut his head.”

“So… Genya did you eat part of that demon back then?” Nezuko asked. When Genya nodded, she hummed in thought. “Maybe you can use the Blood Demon Art of any demon you consumed?”

“And the Asakusa mission was a while ago,” Tanjiro noted. “Did he really store it for so long?”

“I think… that as I get stronger, I can store more Blood Demon Arts for longer,” Genya suggested. “Maybe.”

“We’ll see as we get stronger together,” Nezuko said with a determined grin. “And now, I just need to learn the Hinokami Kagura.”

“Alright, I’ll start teaching it to you tomorrow,” Tanjiro said. He rubbed his chin. “How would it be called as a Breathing form? Breath of the Hinokami Kagura? Breath of Fire? Would it be similar to the Breath of Flames?”

Nezuko shrugged. “Rengoku-san told me to be very particular about names, and that the Breath of Flames can never be called Breath of Fire. But, I can ask him for details. I’ll send him a crow.”

“Sounds good,” Tanjiro said, nodding again. “We all know what’s ahead of us now. So that’s left is to…”

“Get stronger,” Genya finished for him.

Nezuko yawned. “Sleepy,” she murmured. “Onii-chan and I should probably get back to bed.”

“Wait,” Genya called as they started to leave. “Could you maybe… stay with me tonight? It really does get awfully lonely.”

Tanjiro nodded without a second thought, going back to the bed. Nezuko followed. “Of course, Genya. Though, it might be a tight fit.”

Genya thought for a moment, then shook his head again. He started to shrink. His change wasn’t as extreme this time, but he still became significantly smaller.

“Now?” he asked, his voice rising in pitch.

Nezuko beamed. “Now it’s perfect.” She laid down on the side closest to the wall, while Tanjiro took the other side. Genya clambered between them.

“Now it won’t be so hard to carry me around,” he murmured. He still sounded sleepy.

“Yeah,” Tanjiro said, gently patting his head. “I’m sorry this came about this way, but I’m really glad you learned how to shrink.”

Genya smiled. “Me, too. I’m really happy right now.”

~~~

Zenitsu got another check up and joined the rest of them for rehabilitation. He took the challenge head on, for once discarding his cowardly persona.

As they continued healing and regaining their strength, Aoi became easier to beat. Soon, all four of them began to overpower her in reflex training and full body training.

However, Kanao remained unbeaten. Nezuko came close a few times in reflex training, successfully grabbing a cup, only for it to be blocked and for her to be drenched in stinky medicine water. She was even harder to best in full body training, successfully evading each of Nezuko’s attempts to grab her. The three boys didn’t get any closer.

Zenitsu’s burst of confidence dwindled after countless losses as the failure reduced him to tears.

“I’ll never get it! I’ll never be good again!” he would wail to Nezuko.

“Come on, I believe in you, Zenitsu!” Nezuko would try to encourage him. “Of course you need to adjust to it after being bedridden for so long. But you’ll be back in shape with some hard work!”

Zenitsu shook his head. “Nope, I’m done. I’m done for the day.”

“But you only tried twice!”

Inosuke felt similarly discouraged. “I can’t believe I keep losing,” he groaned. Somehow, his disappointment was clearly visible through the mask. “I’m King of the Mountain, dammit!”

It only took a few days for Zenitsu and Inosuke to give up entirely and stop coming to training. Tanjiro and Nezuko only doubled down on their training. They would go through their exercises, and Tanjiro would guide Nezuko through the Hinokami Kagura.

A week later, Nezuko’s crow returned with a response from Kyojuro. He had asked her to meet her outside the Butterfly Mansion gates during the afternoon.

“He probably has some answers about the Hinokami Kagura,” she told Tanjiro. He nodded, excited for potential new information.

After the short lunch break, Nezuko told Aoi she was heading out for a bit. Aoi nodded and waved her out. “Don’t go too far, and don’t forget to come back.”

“Don’t worry, I will,” Nezuko said. She was still dressed in the Butterfly Mansion garments paired with her usual zori sandals. She left the training hall and headed for the Mansion gates.

True to his word, Kyojuro was waiting outside the gate. He had his usual ecstatic smile when he saw her.

“Young Kamado!” he greeted her. “Is rehabilitation going well?”

She offered him a quick smile. “I’m making progress, Rengoku-san.”

“Good. Very good,” he nodded. “Once you’re all healed, you can start incorporating the next part of Breathing mastery.”

“The next part?” Nezuko thought for a moment. “Oh, is it that Total Concentration Constant technique you mentioned a few times?”

“Yes. The ability to use Total Concentration Breathing around the clock can make all the difference,” Kyojuro said. “Make sure your brother learns it, as well.”

“I’ll start drilling it tonight.”

“As expected from my tsuguko. Now then, please tell me in detail what you wanted to discuss.”

Nezuko nodded, pausing for a moment to formulate her thoughts. “When onii-chan was fighting against Lower Moon Five on the recent mission, he used a dance we passed down our family for generations known as the Hinokami Kagura. It turns out it is actually a Breathing technique.”

Kyojuro listened, silently nodding. “I see. Dance of the Fire God. And you two are wondering if it is related to Breath of Flames.”

Nezuko nodded.

“Well, I’ve never heard of the Hinokami Kagura!” Kyojuro declared. “And, unfortunately, I’m on my way to a mission, so I cannot give you any extensive help at the moment. However, my father maintained extensive Flame Pillar archives, detailing the experiences of all the Flame Pillars of the past. If you wish, you can go to our estate at any time. I’m sure Senjuro would be delighted to help you.”

“Alright, I’ll try to go there once my rehabilitation is complete,” Nezuko said. “Thank you for your advice.”

Kyojuro nodded. “And I must thank you for broadening all of our horizons.” He paused for a moment. “With the revelation of your eldest brother, there are many more things that we must consider.”

Nezuko crossed her arms, looking down. Even if Genya was doing better now, his pain still weighed on her. Her anger towards her mentor was significantly lesser than her fury at Sanemi, but the tinge of betrayal was still there. His stance during the trial only solidified the seeds of distrust in her heart, knowing she was right to not tell him before.

Kyojuro clearly noticed her disenhearted face. “I have reconsidered the questions you asked me a while ago. About what I would do if one of my family members was turned into a demon. Before, when the thought of a demon not eating humans could be considered ludicrous, the answer was easy. Now, the situation has gotten far more complicated.”

He gave her another radiant smile. “Do not despair, Young Kamado! No further harm will come to your brother! That is Oyakata-sama’s decree. The Pillars have all memorized his presence, and we will extend our protection to him.”

Nezuko nodded. That declaration brought a slight comfort to her.

“Well, I must get going!” Kyojuro announced. “It was good to see you. Best of luck in your training!”

He took off, vanishing from sight in an instant.

“So you can move like that if you’ve learned Total Concentration Constant?” Nezuko asked herself. “It would be great if we could learn it soon.”

She turned to head back into the Butterfly Mansion, but she spotted movement out of the corner of her eye.

“Oh, it’s you.” Sanemi’s voice.

Waves of anger coursed through her. Nezuko clenched her hands into fists as she turned around.

“What do you want?” Her question came out as a growl, anger brimming and boiling over. “If you want to hurt my nii-chan-” she noticed the faint grimace that came over his face, “then I’ll-”

“You’re talking to a superior officer, you brat,” Sanemi replied. “And besides, we’re not supposed to touch the demon on Oyakata-sama’s orders. So even if I wanted to do something-”

“I don’t care if you’re my superior officer,” Nezuko countered. “We’re talking about family right now. And I won’t let you hurt Genya. He’s suffered enough.”

Sanemi scowled. “This isn’t your business-”

“It is my business because he’s my big brother!” Nezuko yelled. Something within her had snapped. “You left him behind to wander by himself! He was alone, and cold, and scared when he found us. He’s dreamed of reuniting with you for so long that he takes the blame for everything! And the second he finds you, you try to kill him! I don’t care if you still love him, or if you’re doing what you think is best. Family doesn’t treat each other like that!”

She realized she was crying. Sanemi’s scowl was gone, replaced by something entirely unreadable. She glared at him for a final time.

“Genya deserves better than you. And you don’t deserve him.”

With those words, she whirled around and marched back to the Mansion. Sanemi stayed rooted to the spot.

“He… deserves better,” he repeated softly.

He understood that perfectly well. He couldn’t be the big brother Genya wanted, needed, and deserved. That big brother died eight years ago. That big brother was immortalized in the crude drawing Sanemi spied in Genya’s box.

And Sanemi had killed him again.

Sanemi had no place in Genya’s family. He belonged to his mother and younger siblings, to the two Kamado brats. He wasn’t alone anymore, he had a family.

Sanemi just wasn’t a part of it.

Genya didn’t need him anymore.

He turned around, leaving the Butterfly Mansion grounds without even passing through the gate.

Everything Nezuko had said was correct.

He didn’t deserve Genya, and Genya deserved a lot better than him.