Chapter Text

Prologue

Mugen Train

As Rengoku finished his final speech, he began to slump forward a bit with all of his muscles weakening and burning ferociously; his vision beginning to blur significantly as well, and his senses beginning to dull. As he began to close his good eye, however.. he noticed a bright figure appear behind Young Kamado --who was sobbing in front of him-- that made the hashira quietly gasp with surprise and widen his eye. The sound around him seemed to fade and disappear as he looked at the ghostly women, and focussed on who she might be. ‘Mother?’ He thought as he stared at her in awe. ‘Mother.! D-did I do well? The responsibility I-.. I took upon myself to fulfill.. Was I successful?’ He asked, feeling overall dizzy from his wounds and somewhat anxious for her response, yet simultaneously happy to see her. He could feel his weakening heart begin to palpitate and ache with this question, although.. he couldn’t tell if he had actually said it out loud. He sat for what felt like all of eternity, and yet also what felt like no time at all, before he got his response. 

“I’m so proud of you, my son.” His mother replied. Her voice sounding angelic and sweet; soft and warm; happy and loving. 

The statement filled Rengoku’s failing heart with an immense joy and made it feel as if it had warmed despite its now unstable pattern. He could feel his bright smile quickly return as he let out some pained breaths of happiness. He could feel himself weakening more as he slowly continued to slump forward.. but just as he closed his eye and began accepting his fate.. he began to feel two gentle hands take hold of his shoulders, then envelop him in a soft hug. They couldn’t have been from Kamado.. The movements were too gentle and calm, and before the Hashira could look up to see who it was, he heard his mother’s voice once more, but much closer this time. ‘It must be her in front of me.’ He thought as he did his best to rest his weary head on what he assumed to be her chest --when in reality, there was nothing in front of him but air-- and he listened to her intently. 

“You've done so well, and I am so proud. I look forward to being by your side again… however.. It is not your time yet. Just don’t let the disease take you. ”

Her voice remained gentle and sweet, but Kyojuro could only hear those words before everything around him, including her, faded. His consciousness had left him, and his whole body relaxed after one final, gentle, twitch.

Kamado and the others watched as Rengoku’s body went still, and their sobs intensified with sorrow and grief for the Flame Hashira. Tanjiro’s and Rengoku’s crows wept as well, but quickly began flying away to inform the other Demon Slayers and Kakushi of their location. 

Eventually the Kakushi arrived to help with the cleanup and were also unsettled by the sight before them. The three young Demon Slayers were sobbing and wailing, meanwhile the Flame Hashira sat limp and unmoving. They assumed the worst and immediately went to see if the boys were ok. They assessed that Tanjiro was injured the most out of the three, but were urged by the boys to check Rengoku, just to be absolutely sure that he was gone. The Kakushis sighed with heavy hearts and checked the temperature, pulse, and breathing of the Hashira. They expected him to be cold, seeing as most of his blood was either on/in the ground or soaked into his clothes, but instead, they felt something odd. 

Chapter One:

The Butterfly Mansion

It had only been a week after the Mugen Train incident. The young Demon Slayers and Rengoku were all safely transported back to Lady Shinobu’s Butterfly Mansion, and the boys were doing “ok” at best. Tanjiro’s stomach wound was still healing and aching, and the others were worn out and discouraged; worrying more for the Hashira that they failed to rescue in time. They were all aware that he was still alive, but considering that he was mortally wounded, it felt more like a failure on their part. 

Due to the severity of his wounds and the amount of treatments he would likely need, they kept Rengoku in a separate room from the others and checked on him frequently without allowing any visitors. He remained asleep for the whole week, and the ones keeping an eye on him noticed something that was rather odd and suspicious about him; another reason they kept him somewhat isolated. 

Upon arrival, he had a horrible fever and was barely breathing, but now that he had rested, was treated to the best of their abilities, and had some blood put back into his system, his wounds were beginning to heal.. But not at its normal slow rate. The cut on his forehead, along with some other small cuts and bruises were completely gone by day three, and his smashed eye seemed to be doing better too. The most bazaar and concerning thing however, was that the large hole through his torso had nearly vanished; some scar tissue and little scabs being the only reminder of a previous wound.

Aoi, the main person in charge of checking up on Rengoku, had just learned this fact and decided to run off to go warn Shinobu. Although Rengkou wasn’t awake and posed no threat yet, it was necessary to tell another Hashira about this concerning discovery.

Upon learning the news, Lady Shinobu ordered Aoi to go back to Rengoku, then finished up what she was previously doing, and began heading to his recovery room as soon as possible. On her way there however, she was interrupted by the voice of a certain flashy man. 

“Hey, Shinobu!” Tengen called out as he began following her.

She sighed and looked back at him. “What is it, Uzui?” She asked, already annoyed with him since he had already bugged her about visiting Rengoku the day before.

“You’ve kept my Best Buddy locked in that room for a whole week.! I wanna see him already!” He responded as he swiftly caught up to her, now walking beside her. “The report said he nearly DIED! And I’ve been worried about him.! So let me go see him, damnit!” He demanded, but didn’t really sound all that mad; more frustrated than anything. 

Shinobu let out another sigh before attempting to walk faster than the other. She wasn’t faster than Tengen by any means, but did manage to get in front of him as they entered a slightly narrower hallway. “I’ve kept him mostly isolated so he can rest, Uzui. He doesn’t need your loud mouth disturbing him.” She responded with her annoyance now showing. “Plus, you sent your wives off alone into a very dangerous place. If I were you, I’d worry more about them, rather than someone who’s safe and in need of rest.” 

Tengen’s frustration turned to anger as she spoke, feeling somewhat offended. “Are you implying that I don’t care about my wonderful wives?!”

“I never said that.. Now go somewhere else, I have something important to look at.!” She insisted, approaching the doors that led to Rengoku’s recovery room. 

Tengen rolled his eyes and let out a sigh before turning around. “Ugh.! Fine!” He then rounded a corner and pretended to leave.

As he “left,” Shinobu entered Rengoku’s room and approached him to see what was wrong. As she did this, Tengen silently came back to the door but didn’t enter, instead, he put his ear to the door and tried to eavesdrop on what Shinobu was doing. 

“So, Aoi. What exactly is the issue?” Shinobu asked quietly as she picked up some things to help analyze him.

“Well.. most of his wounds are gone.” Aoi stated worriedly. 

Shinobu looked a bit confused and turned to face the unconscious Hashira. She noticed that his bandages had been previously removed by Aoi, and almost instantly saw that yes, the wounds on his face were almost completely gone. She furrowed her brows a bit with slight discomfort before gently moving Rengoku’s eyelids a bit. She saw that his left eyeball was black instead of white, but it also seemed to have nothing to do with the now healed injury; it made a wave of unease wash over her. She then decided to lift his shirt a bit, revealing his almost healed stomach. Her expression became one of surprise immediately afterwards, and she began to ponder. “Hm..” As she thought, she decided to check Rengoku’s other vitals and could tell that something was definitely off. 

“Well.?” Aoi muttered, unsure of what to do in this situation. 

“Did Nezuko or Tanjiro stop by at any point? Nezuko’s Blood Demon Art seems to heal some damage dealt by demons, but I’m not sure if she would be able to heal this.. I’m also not sure if it would explain his black eye either.. But It’s not completely off the table, so I’d like to know. I don’t want to immediately jump to any harsh conclusions..” Shinobu asked, her voice slowly becoming a mutter as she pondered every other possible thing besides the obvious.

“They stopped by, but I didn’t let them in. They seemed worried about Mr. Rengoku, but they left once I insisted that he needed rest.”

“Hm.. Perhaps you should go get them for questioning. Maybe they snuck in while we were sleeping?”

“Uh.. ok.!”

Shinobu decided to rebandage Rengoku’s face partially to hide his eye as Aoi soon approached the door and opened it to leave. Tengen had been standing there the whole time, listening closely, and had decided against hiding as the door opened, and instead barged right in.

“Hey! You’re not supposed to be in here!” Aoi protested.

“Aw, hush.! I can do whatever I want when it comes to being concerned for my Best Buddy. Just go find the demon girl!” Tengen responded as he approached Shinobu, soon looking at Rengoku.

Aoi began to protest more, but Shinobu decided that since he was already within the room, there was no point in trying to shove him out again, so she ordered Aoi to just find Tanjiro and Nezuko. Aoi reluctantly obeyed and shut the door as she left.

“So. That’s why you don’t want anyone coming in here. You think my Best Buddy’s a demon.!” Tengen complained with frustration before inspecting Rengoku closer. He moved the bandages a little, having heard Shinobu’s comment on his eyes, and decided to do the same thing she did. He looked at the black eye and became very confused and a little unnerved.

Shinobu ignored Tengen’s words for a moment, but scolded him for moving the bandages. He put them back and stood aside, thinking, as Shinobu checked Rengoku’s heartbeat. She could instantly tell that it was beating much stronger than it should be in his condition, and she looked somewhat bothered by it. When he first arrived, it sounded as if his heart was struggling to do anything; however, now it sounded fine. She hummed with concern at this and decided to try something. She approached the window nearest to Rengoku’s bed and opened the curtains. The evening sunlight poured into the room, but not onto Rengoku directly since the window was on the same wall his bed was pressed against. She then moved out of the way to set her things down. “Tengen, would you mind putting his hand into the light?” Shinobu asked quietly.

Tengen let out an annoyed huff before gently taking hold of his best friend’s hand and pulling it into the soft ray of sunlight. His hand didn’t immediately burn, instead, it looked normal. “What the hell.?” Tengen quietly questioned himself, staring down at his friend. “If he’s a demon, then why isn’t he burning?”

“Maybe he hasn’t fully become one yet?”

“But he’s already healed himself. Only demons can do that.”

“Hmm...”

“Although, here’s another question.. I thought only Muzan could turn people into demons. Muzan wasn’t there.”

“That was the theory, yes.. But perhaps now the Upper Ranks can do it too? Apparently he was offered to become a demon, but he blatantly refused.. so he didn’t do it willingly. How is this even happening?” Shinobu replied, mostly thinking out loud. 

“This is bullsh-” Just then, Tengen cut himself off, having heard a quiet huff escape the lips of his unconscious friend. 

The two immediately looked towards Rengoku with worry, and watched as he sleepily struggled to open his unwrapped eye. Shinobu grasped her sword handle and sheath just in case, meanwhile Tengen slightly tightened his grip on his friend’s hand, stupidly hoping to comfort him in an attempt to prevent him from going crazy, like most demons do. 

“Hey! How’s my Best Buddy feelin’?” He asked, sounding a little awkward considering the circumstance.

Rengoku heard the question and had to take a long moment to process; not even entirely being sure if the sounds he had heard was even a question in the first place. He didn’t say anything in response and soon gripped Tengen’s hand in return, simply because it was in his own. He continued to lie still and quiet for a few moments, feeling very out of it and loopy. After these long few minutes, he ended up letting out a tired sigh and decided to slowly open his eye and glance around the room. His vision was a little hazy as it danced around sleepily until finally it landed on Tengen and Shinobu, which caused him to develop a look of confusion.

“Hey, Best Buddy.” Tengen repeated, smiling with worry at his friend.

As he heard the other speak, Rengoku’s vision finally began to clear. “Best.. Buddy….? Uzui.?” Rengoku muttered tiredly and with confusion.

“Mhm. That’s me! Your glamorous and flashy best friend!” Tengen said with a bit more enthusiasm than before, seeing as how Rengoku wasn’t going insane yet.

As Rengoku laid there and stared at his friend, it was clear that the gears were turning in his head for a good moment. Once he finally snapped out of it, he perked up a bit through his exhaustion, and his signature smile began to form. “I’m alive!” He stated merrily, gripping his friend’s hand tighter.

This comment surprised the two Hashira, but Tengen soon smiled genuinely and gave Rengoku’s head a pat. “Yeah! You’re still here! And from what I heard, your last battle was very flashy!”

Rengoku couldn’t help but let out a quiet giggle at the gesture, meanwhile Shinobu sighed and let go of her sword to tug on the back of Tengen’s shirt, signaling for him to step away from Rengoku; just in case. Tengen eventually let go of his friend because of this and instead decided to lean against the wall near the previously mentioned window. 

“So. How ya feeling?” He asked with a smile.

“Well..” Rengoku paused. “I’m not entirely sure. But I feel much better than before.! I suspect that I’ve been asleep for a long time. I’m also a bit hungry.” He said cheerfully, yet still seemed tired, his eyelid feeling heavy.

Tengen and Shinobu shared a concerned glance for a few seconds before Tengen perked up again. “Yeah, it’s definitely been a minute, that’s for sure. I mean, your face is almost completely healed now. But you still need a bandage” He lied convincingly.

Rengoku seemed surprised by the statement, but not for long, regaining his smile quickly. “I see, that is good! How are Young Kamado and the others doing?” He asked curiously.

“They’re doing just fine. They’re still a little down about everything, but they’re doing much better.” Tengen said happily before glancing at Shinobu again. “Ya know, Shinobu did ask that Kamado be brought here.” He added, his tone changing to a mix of worry and annoyance.

“Ah. I suppose I did.. Well, we’ll cross that bridge once we get to it, I suppose.” She responded with a slightly more reassuring tone, but still sounded a bit worried.

“Is it a bad thing for Young Kamado to be here?” Rengoku asked curiously.

“No, it’s not that. It’s just… You’re still healing and we…. don't wanna crowd you.!” Tengen sounded a bit awkward with his words, but Rengoku did his best to ignore it. Perhaps they were just stunned that he was even awake at all.

“Well, I don’t mind visitors. The more the merrier.!” Rengoku said happily. “I’m sure Young Kamado was worried about me. Him stopping by to say ‘hello’ surely won’t kill me.” He added, actually being eager to see the boy to make sure that he was ok. 

“Yeah.. I guess that’s true.” Tengen muttered, still sounding worried. It was mostly due to the fact that Kamado and the others were still injured and Rengoku had mentioned that he was hungry. Keeping the previously bloodied children away from him seemed to be the better option here, but because of Shinobu’s previous request, they now need to be more cautious. Tengen then took a breath and decided to change the subject. “Ya know, you’re incredibly lucky to still be alive right now. We were honestly all surprised, considering the damage.”

Rengoku hummed in agreement and took a moment to remember what had happened. His smile soon became a sad one, and he glanced at the edge of his bed, simply to look away from the Hashiras. “I’m surprised, myself. Although.. Interestingly enough, in what I thought to be my last moments, I believe that I saw.. my mother.”

Shinobu and Tengen both looked surprised, but they remained quiet, curiously awaiting the rest of his story.

“She appeared to me while I was feeling woozy, and she told me that she was proud. I remember smiling and accepting my fate, assuming that I would soon join her, but then I heard her tell me that ‘It’s not your time yet. Don’t let the disease take you.’ I don’t really know what she meant by that, and I don’t remember anything after it. I believe that is when I fell unconscious.” Rengoku said with his sad and tired smile remaining, it seeming as if he missed his mother. 

Shinobu took mental note of what his mother had said; meanwhile, Tengen understood his friend’s look and his expression also became one of slight sadness. He opened his mouth to say something, but was unintentionally interrupted. 

“Even if I don’t heal fully, and end up having to retire as a Hashira, I still wish to help the Corps as much as possible. Perhaps I could help cook food for everyone or help with training?” He suggested, his smile and optimism returning with every word. Then he looked at his Best Buddy again, who was now looking at Shinobu with an even sadder look in his eyes. Rengoku’s smile wavered a bit, but his optimism did not. “Even if I’m not permitted to stay here once I’m healed, I don’t intend on sulking. I hope to be able to return home and care for my brother and father.! It’s what my mother would’ve wanted.” He added happily, but soon felt his concern begin to grow, seeing as how the others failed to reply.  “What’s the matter?” He questioned, then watched as his buddy looked at him with concern behind his smile.

“We haven't decided what you’ll be able to do once you’re better. And we’re concerned for you. That’s all.” Tengen responded, doing his best to sound reassuring as he carefully worded his sentence. He hadn’t really been lying to his friend, but he wasn’t completely honest either. The truth was, he wasn't sure if they’d even be allowed to keep Rengoku alive.. considering that he’s now seemingly a demon.. But he didn’t want to worry his friend, so he refrained from mentioning anything relating to it. “I’m just so glad you're your same happy self.”

Rengoku nodded at the response with understanding, and smiled once more. “Me too. And I’m sure whatever you decide will be what’s right for me. I just hope that I’ll at least have a chance to say goodbye to everyone, if I end up having to leave.”

It pained Tengen to think that they might have to slay Rengoku, especially after what he had just said, but he did his best to conceal his worries. He was about to continue their conversation when he was once again interrupted, but this time by a knock on the door. 

“Ms. Shinobu?” Aoi called from outside. “Tanjiro and Nezuko are here, just like you asked.”

Shinobu sighed and approached the door, opening it enough to stick her head out. Tanjiro stood there with his recovery attire on and Nezuko’s box on his back. He smiled at the Hashira, and greeted her warmly. “Hello, Ms. Shinobu! You wanted to speak to Nezuko and I?”

“Yes, I did, but wait just a moment.” She said to Tanjiro before looking at Aoi. “Thank you for helping, Aoi. You can have a break now, if you wish.” She said with a small smile, receiving a respectful nod in return before Aoi left.

“How’s Mr. Rengoku doing?” Tanjiro asked curiously.

“I’m doing just fine!” Rengoku called out happily from inside the room, having heard Tanjiro. It now seemed as if his hearing had improved too, alongside his injuries.

“H-He’s awake?” Tanjiro asked with almost complete shock.

Shinobu sighed and nodded. “Yes, he is..”

Tanjiro’s face lit up at the response and he moved his head to try and peek around her, but to no avail. “Can I see him?” He asked eagerly.

“Well--”

“Of course you can!” Rengoku interrupted joyously, happy to be able to see the young Demon Slayer.

Tengen repositioned himself a bit and watched closely as Shinobu reluctantly let Tanjiro come in and immediately approach Rengoku; although, Tanjiro’s enthusiasm quickly disappeared, being replaced by worry. ‘This scent… He smells.. different..’ He thought as he looked at the Hashira. 

“How are you doing, Young Kamado?” Rengoku asked happily.

Tanjiro did his best to ignore the new smell and soon smiled back, putting a hand where his wound was. “Well, it hasn’t really healed yet, but I feel much better. How about you?”

Rengoku then looked confused and glanced at Tanjiro’s hand. “I’m feeling almost as good as new! But your wound still hasn’t recovered?” He questioned.

“No. It’s only been..” He paused and quickly took on a look of confusion and concern. “It's.. only been a week..” He continued, sounding somewhat unnerved.

“What?” Rengoku questioned, then decided to feel his once injured forehead out of confusion. “A week?” He muttered, then glanced at Tengen.

Tengen put a hand on his face and let out a long sigh before nodding. “Yeah.. A week.”

“Then how am I..?” Rengoku wondered aloud, but didn’t bother finishing his sentence.

“Hang on..” Tengen muttered with defeat.

Rengoku watched with confusion as Tengen pulled a mirror from his pocket, then proceeded to take off his (Rengoku’s) eye bandage. He gave Rengoku the mirror and instantly, Rengoku’s and Tanjiro’s expressions changed to horror. Rengoku stared back at himself and saw his now very black eye. His irises and pupils looked mostly the same, but they had a light glow to them. Upon seeing this, the Flame Hashira quickly sat up before checking his stomach. He froze upon seeing that the wound was nearly gone, and he began to question everything. 

“M-Mr. Rengoku.!” Tanjiro blurted with disbelief.

Rengoku stayed silent for a moment as he stared down at himself and continued processing. “But.. I.. I feel normal.! I’m not aggressive or thirsty.! Or.. at least.. I’m not thirsty for blood.!” He said in a somewhat panicked tone. “I feel completely fine.. just… tired..” He added, looking to Tengen again. 

“I know.. That’s the issue. You’re completely the same so far. You don’t even burn in the sun. But you must be a demon. Why else would you heal so fast and have that weird black eye?” He said with slight annoyance. ‘Out of all the people this could’ve happened to, why did it have to be my Best Buddy?’

“...” Rengoku stayed silent for a moment, staring down at himself, still in disbelief. After some time, however, he shifted his gaze and glanced up at his Best Buddy. “Are you going to kill me?” He asked with his seriousness returning, also sounding devastated. 

Tengen’s heart ached a bit at the question, he then shook his head. “No. Not yet. Like I said before, we haven’t decided what to do with you. We only just now found this out.” He responded with as much reassurance as he could muster.

Rengoku sighed and glanced over to Tanjiro, who was clearly very upset. “Young Kamado. Do you remember what I said a few days ago?”

He nodded in response and looked at the floor with frustration. “I do. And I will still talk to your family. Just give me some time.” 

“You are very kind.. And I thank you. If I had to add anything to my statement, it would be: ‘Tell my brother and my father that I love them.’ Although I'm sure they already know that. ” Rengoku said with a somewhat saddened tone before deciding to lie back down. 

Shinobu let out a sigh before taking hold of Tanjiro’s sleeve. “I would like to talk with you in private for a moment, if that’s ok.” She suggested, receiving a nod in return. 

The two soon left the room, leaving Tengen and Rengoku alone. They laid and stood quietly for a little while, until Tengen decided to sit on the side of Rengoku’s bed. 

“Listen, as long as you don’t hurt anyone, I won’t let them kill you.” Tengen said with all seriousness.

“It’s not really your decision, Best Buddy.. but I thank you for your kindness.” Rengoku muttered, looking a bit sad or upset with himself.

“Listen, if I have to do what Tomioka and that kid have to do, then I will. You’re my Best Buddy and I know you wouldn’t hurt anyone. Look at you! You’re lying here almost completely the same! Even while you're hungry, there’s not an ounce of aggression or bloodlust in you.” Tengen said in return before looking at Rengoku. “If anyone can overcome being a demon, it’s you!” He then took a short pause as if he were mentally debating something. “And that weird girl in the box..” He continued, hearing his friend let out an amused exhale. “But don’t let this discourage you. You gotta follow your own damn advice. ‘You may feel like digging your heels in, but time waits for no man. Not even as you grieve.’ Or.. whatever it is that you said.. I overheard it from Kamado, yesterday..” 

The little speech made Rengoku’s smile return, resulting in him slowly sitting up again and pulling Tengen into a hug. “Thank you, Best Buddy!” He said happily, soon feeling Tengen squish him in a big bear hug.

“Of course, Best Buddy.” Tengen responded happily as he gave Rengoku one final squeeze, finally loosening his hug afterwards to a normal one. “Just don’t go scaring me like that again. We can’t have the only person flashier than me die. What an awful tragedy that would be!” He added dramatically, causing Rengoku to laugh a bit. 

“If the Corps allows it, then I will do my best to stay alive and be flamboyant with you for as long as I can.” Rengoku then gave his buddy a pat on the back and leaned away before clearing his throat. “But I think my first course of action will be to return home.”

Tengen smiled at his friend as he spoke, and soon stood up from the bed. There was a pitcher and some empty glasses across the room, and he decided to walk over to them. “Sounds like a plan to me. Now, want some water? You said something about being thirsty..?” Tengen asked as he poured two glasses of water.

Rengoku let out a “Mhm” in response and was soon given a glass. He drank it slowly, unsure if his stomach had healed enough for him to consume anything, but as he continued, he felt better and better; So he assumed that perhaps he was fine. As the two finished their drinks, they soon heard the door open again, causing them to look over and see Shinobu again.

“Rengoku. Do you think you’re able to walk?” She asked curiously. “I told Tanjiro and his crow to inform the other Hashira of what’s going on. We’re going to have an emergency Hashira meeting to determine what we should do with you.”

“Perhaps I can, though I’m not sure.” Rengoku responded before giving his glass to Tengen. He then slowly moved to the edge of the bed and stood. He seemed a bit uncomfortable as he did so, and eventually fixed his shirt before putting a hand on his belly. “My stomach aches a bit, but I believe I'm ok.”

“Was it the water?” Tengen asked as he set the glasses aside.

“No, I think it’s either: I haven’t fully recovered yet, or it’s simply because I’m starving.. It’s hard to say.” Rengoku then let out a soft and tired huff before making his way to Shinobu. 

“Well, let’s hope you don’t get hungry enough to eat us.” Shinobu commented with slight annoyance, opening the door a bit wider for him.

“I can assure you that I have no intention of eating anyone, but I understand your concern.” Rengoku then smiled a bit before exiting the room.

Tengen followed, and helped escort the Flame Hashira to the other end of the Butterfly Mansion. Rengoku seemed mostly fine as they all walked, but Shinobu did her best to keep a close eye on him, monitoring his every subtle movement. The only thing he did on the way out that could be considered a concern was glance in the direction of the other recovering patients’ rooms as they passed them, but it could’ve been for a multitude of reasons, so she didn’t mind all that much. Eventually, they all reached a covered porch where they stood and waited within the cool evening air. Within that time, Tengen tried to fix his buddy’s hair so it wasn’t a mess, and did his best to make it look more presentable. He did this mostly out of boredom, but Rengoku didn’t mind in the slightest, seeing it as a simple show of affection and care. At around dusk, most of the other Hashira had arrived, and they already had their suspicions and doubts which caused them to mutter amongst themselves. Mitsuri was the only Hashira missing, but this was due to her having been somewhat far away when summoned. Apart from her, they were waiting on the Master, needing his input on the situation as well. They waited and waited for what felt like forever, and within this time, Rengoku still seemed fine, just tired and achy. At some point, he had sat down, and at some other point, Giyu and Tengen had sat beside him, only Giyu was slightly farther away. Sanemi had scolded the Water Hashira for this, but he didn’t seem to care, and remained silently seated. 

Everyone talked and debated amongst themselves for a while until finally the Master had arrived. As he softly greeted everyone, they all fell silent and kneeled, politely greeting him with respect. 

“I hear there has been an incident regarding the Flame Hashira.?” The Master asked, his voice as smooth and sweet as usual.

Tengen let out a sigh and glanced at Rengoku. “Yes, Master. We regret to inform you that Kyojuro Rengoku.. has become a Demon.. We think.” 

“Is that so? Where is he now?”

Rengoku perked up. “I am here, Master. Although, I have done no harm yet.” He answered honestly.

“You certainly don’t sound like a demon. I wish to hear of what happened upon your awakening.”

Everyone soon sat up and briefly looked at Rengoku, but Shinobu and Tengen gave each other a nod before explaining honestly. They both mentioned that Rengoku seemed his usual self other than his regeneration and his eye, and both vouched for him individually. Shinobu suggested running a test and Tengen agreed, but asked that it wasn’t anything brutal considering what he has just been through. The Master thought for a moment before agreeing, and suggested that they do a similar test to Nezuko’s. Sanemi stood almost instantly after hearing that, almost seeming excited, but he was soon interrupted. 

Tengen had stood up too, and looked over to Sanemi. “I don’t think it should be you who performs the test. You’re too aggressive. You stabbed the demon girl a lot last time. My Best Buddy can’t handle that right now.” He protested.

“Then how are we going to test his regenerative abilities, huh? That helps determine how powerful of a demon he is. We gotta do something to him.” Sanemi responded, drawing his sword.

“I understand that, but we don’t have to stab him.”

Rengoku soon stood and let out a quiet sigh. “I don’t mind what happens to me in order to test if I’m dangerous. If he must stab me, then let him stab me.” He said, looking over at Tengen. “I thank you for trying to defend me, but if we’re going to do this, I wish it to be done properly. I don’t want this test to be performed wrong. What if I end up hurting someone afterwards? Not that I intend to..”

Tengen thought for a moment and let out a frustrated sigh, standing back and allowing for Sanemi to get a bit closer. The sun was now setting, and immediately, they could see another interesting feature about the Flame Hashira. His good eye seemed to be dimly glowing. Shinobu decided to light some lanterns all around the area to better see what was happening, and all the other Hashira decided to put some distance between Rengoku and themselves. Rengoku was soon told to get off the porch, because he was near the Master, and he did just that. Meanwhile, Tengen moved to be standing beside the Master to potentially protect him if needed. Once everyone was in place, the test began. 

Sanemi soon gripped his sword and took a swift and strong stab at Rengoku’s already wounded stomach. The attacks caused him to wince and stagger. He nearly fell from the force of it and it obviously hurt him quite a bit. He huffed for a moment and began to hack up some blood, but soon enough, his wounds began healing, but it was quite slow. 

Sanemi allowed the Flame Hashira a moment to breathe and heal before slashing at his own arm, like he did for Nezuko, and plunged his blade into Rengoku’s stomach a second time; this time keeping it there. 

The attack caused Rengoku to yelp a bit louder than before with immense pain, and he began coughing up even more blood. He winced and lightly panted at first, but quickly fell silent and still. His gaze now focussed on Sanemi’s wound. His eye widened and his pupil shrank a bit, the white eye turning black, and his iris glowing brighter. He began to drool profusely, and it seemed as if he forgot about his own wounds in an instant.

 Sanemi grinned at the Flame Hashira, and soon yanked his blade from his body, causing him to gasp and gag on his own blood, then fall forward. He caught himself with his hands and sat on his knees, looking up at Sanemi with what looked to be rage, but it most likely wasn’t; meanwhile his blood spilled onto the ground from his open stab wounds. 

Tengen seemed pained by the sight, but still brandished his blades in preparation, and awaited the outcome of this gruesome test. 

Rengoku gripped at the ground beneath him, and did his best to swallow his bloody drool, but it just couldn’t be stopped. He stood after a couple moments and began to growl. 

Sanemi watched him closely and soon noticed his wound closing. With this, he raised his sword in preparation to stab him again, but refrained from doing so, watching and waiting to see what the demon would do. 

Rengoku stared intensely at Sanemi’s wound, and continued to growl and salivate, but he never made a move. He just stood there and struggled with his newfound bloodlust. 

After another couple of minutes, Sanemi had an idea and glanced over at Tengen. “Someone take Uzui’s place!” Sanemi demanded openly. “I wanna try something.”

Tengen hesitantly moved away from the Master, meanwhile Obanai --looking a bit upset as well-- quickly took his place. “What? Ya want me to cut myself too?” Tengen questioned somewhat sarcastically as he approached.

“Yes, now let me do it. I wanna see what happens.” Sanemi responded as Tengen set down his massive cleavers.

Sanemi wiped off his blade before taking hold of Tengen’s arm. The two watched Rengoku’s movements closely, and noticed his gaze following Sanemi’s hands. Sanemi raised his sword and cut into Tengen’s arm just barely enough for it to bleed, and watched as Rengoku took a step forward then proceeded to growl louder, now looking at Sanemi. 

Their attention quickly went back to him as they raised their arms in front of him, and waited patiently to see what would happen. Tengen slowly reached down for his cleavers as he watched his buddy get even closer, and watched him intently, even taking a few slow steps back. He also happened to notice that his Best Buddy’s teeth looked normal. They weren’t long and sharp like a demon’s.

Rengoku still continued to drool, but kept his gaze on Sanemi, now looking even more angry than before. He slowly stepped closer to his buddy, but kept his back to him, and continued to face Sanemi instead. He eventually stopped when he was between them and decided to wipe his mouth on his sleeve. Sadly, it did nothing to prevent the saliva and he continued his loud snarls. 

Sanemi shifted his position a bit, raising his sword in a threatening manner, and Rengoku shifted positions too. Although.. he wasn’t aggressive.. he seemed more protective? This confused Sanemi and the others a bit, so as another test, Sanemi decided to pretend to attack Tengen, and watched as Rengoku did his best to stay between them in a protective manner. 

This test had gone on for quite a number of minutes, and the Master eventually spoke. “What is going on?” He asked softly and curiously.

“He's.. being protective of Uzui, but isn't being aggressive.” Sanemi answered, sounding a little baffled.

It sounded as if the Master was going to speak again, but he was cut off by the sound of a lady’s voice in the distance.

“I’m sorry I’m late!!” The voice shouted. 

The Hashira all looked towards the voice. It was Mitsuri Kanroji. She was running over with a big plate of food, and was apologizing repeatedly.

“I’m sorry I’m late! I’m sorry I’m late! I had to grab dinner before I came! I was starving!!”

Rengoku had also looked towards the voice and watched as Mitsuri ran by with the food. His pupils grew back to their normal size, and he suddenly bolted in her direction. This caused massive alarm for everyone present, and every Hashira, except Mitsuri, quickly unsheathed their swords and jumped to her rescue. Mitsuri screamed from surprise and dropped her plate, but it was quickly snatched back up by the Flame Hashira before it could hit the ground, and everyone quickly froze where they stood; Including Tengen whose cleaver was mere inches away from his Best Buddy’s neck. 

‘He’s eating her food!?!’ Everyone thought simultaneously.

All the Hashira let out a breath in unison as they watched, and Mitsuri couldn’t help but tremble. Obanai hastily yanked Giyu over to the Master before quickly running to comfort Mitsuri, grabbing hold of her, pulling her close, and pointing his sword at Rengoku who was sitting on the ground and stuffing his face with the food. 

“Don’t you ever do that again! Do you hear me?!! You scared the ever living fuck out of us!” Obanai scolded loudly, which was somewhat surprising to the others.

Tengen began to slowly relax by raising his cleaver away from his buddy, and watched as he quickly ate. Once Rengoku had finished eating, he wiped his face with his sleeve once again and yelled out “UMAI!!” The Hashiras then sheathed their swords and sighed with relief. 

Rengoku glanced up at Mitsuri soon after, but lowered his head soon after with respect, his eye also going back to normal. “My apologies Ms. Kanroji! I did not mean to frighten you! I just thought, if I ate something normal, I might calm down. It seems to have worked. I’m very sorry for scaring you.!”

Sounding soft and gentle the Master spoke up. “What has happened?” 

“This dumbass thought it would be a good idea to scare the shit out of us by launching himself at Mitsuri, just so he could steal her food!” Obanai shouted angrily.

“Please try and calm yourself. He didn’t hurt anyone, did he?” 

Obanai hesitated and looked at Mitsuri with concern. “No.. I suppose not..” He muttered.

Tengen decided to prop his cleavers on his shoulder before approaching his buddy from the front. He lowered his bloodied arm to Rengoku, and watched as he turned his head away from it.

“I do not want it.” Rengoku said somewhat sternly.

Sanemi did the same as Tengen, and Rengoku simply turned away from him as well. 

“I meant it. I do not want it.” Rengoku repeated, then slowly stood and began to look around.

Sanemi and Tengen looked surprised, but they didn’t speak. Instead, they took note of the lack of drool on the Flame Hashira’s face, and the lack of rage or struggle he had. Rengoku soon decided to rip up his shirt and wrap their arms with the least bloody bits of it, and gave them both a bright smile. Tengen looked at his buddy’s healed stomach, then to the Master.

“He has bandaged our wounds, has healed his own, and hasn’t attacked anyone. Personally, I think he passed.” Tengen said with a smile before giving Rengoku’s head a pat of congratulation. 

Rengoku appreciated the gesture, then decided to look at the others. “My apologies for alarming everyone.! I promise that I will not do it again.” He stated.

The Master thought for a moment in silence, meanwhile the other Hashira looked to each other, seemingly for reassurance. They were all debating amongst themselves mentally, and the tension was quite prevalent. After a few moments, however, Sanemi broke the intense silence. 

“While it is true that he didn’t hurt anyone, he did scare the fuck out of us and is still very strong! He may be a friend to most of us, but he’s still a demon! I say that he’s still dangerous, and we should just get rid of him!” He said coldly.

Tengen scoffed in return, “Well, like he said, he just wanted some real food to calm himself. And it worked, didn’t it? I think he’s just fine.” 

Obanai held Mitsuri closer and raised his hand to give her head some pats, but gave Rengoku a sour look. “He didn’t have to dart to Mitsuri though. If he was aggressive like we initially thought, he probably would’ve at least cut her or bit her before any of us got to her. He grabbed and ate her food faster than we could get to him!” 

Tengen let out a sigh and took his cleavers off his shoulders, keeping them together and barely stabbing the tips of them into the ground. “Well.. I was holding back some..” He admitted with slight shame.

“WHAT?! Why would you do that! He could’ve killed her!” Obanai scolded angrily. 

Tengen simply stayed silent, not wishing to worsen his case by speaking. Instead, he shifted his weight onto one leg and leaned on the handles of his cleavers.

“You hold too many biases towards him. You shouldn’t be counted in this vote! In fact, doesn’t that count as defending or helping a demon?” Sanemi butted in angrily. He then unsheathed his sword once more and approached Tengen, soon shoving the dull side of the blade against his torso and the handle against his chest. “You and Tomioka can go commit Seppuku together, you pathetic excuses for Hashira! Defending demons, what is wrong with you two!” He said coldly, receiving an angered and offended look from the Sound Hashira, then saw and felt a hand tightly grab his wrist. He looked over and saw Rengoku looking angered, and soon raised a brow in return.

“That’s enough.” Rengoku said with disdain in his tone, and almost looked as if he wanted to deck Sanemi for insulting his buddy, be he refrained and instead let go of his wrist, watching the Wind Hashira scoff and pull his blade away. Rengoku then looked up at his Best Buddy, and they both softened their expressions a little.

Sanemi proceeded to roll his eyes, and Obanai simply looked away and seemed a bit saddened for Rengoku, but they stayed quiet so the others could speak if they wanted.

Tokito stared blankly at the situation, and eventually tilted his head some. “I’m just not sure on this matter. If we keep Rengoku and are sure that he stays docile, then we’ll have an even more powerful Hashira than before, along with a crucial asset when it comes to killing Muzan; however, if he turns and becomes aggressive, Muzan will surely win. The loss of possibly two Hashira would be devastating for us, if Tengen committed Seppuku; but if he stayed, and with Rengoku’s new strength, we could surely kill Muzan. It’s a bit of a gamble.” 

Shinobu hummed quietly with judgment and soon spoke up too. “He may have kept his personality and remained sweet and docile up until now, but we can’t ever be sure that he won’t maul someone. He was struggling before he ate and demons have proven to be a little unpredictable. I agree that Uzui did help him, even if it wasn’t by much. He deserves some punishment, but Seppuku seems a bit extreme.. And as much as I like Rengoku and wish he could stay, I agree with Tokito and think the risk outweighs the reward. We might be better off slaying him for our safety and everyone else’s.” 

Gyomei let out a quiet sniffle as tears ran down his face. “If he has remained the same and vows to never injure anyone, why not let him stay? He hasn’t hurt anyone and has kept his usual state of mind. He’s very powerful already, and could injure us, yes. But if we guide him and make sure he stays true to himself, we should never have to worry about such issues. I say, we let him live.” He said stoically.

Mitsuri let out a sigh and looked over to Rengoku again, keeping hold of Obanai. “He did scare the crap out of me just now by rushing towards me, but I didn’t really see any malice behind it, he just startled me!. He’s also the one who helped me become a Hashira! Since he’s the same as before, just with a little extra sunburn here and there, he should be left alive!” She stated, not sounding all that confident with her tone, sounding a bit biased too.

“He’s a good guy. I don’t want him to die..” Giyu muttered, then glanced at Tengen.

The Master took another few moments to think after hearing everyone’s opinion, and eventually nodded to himself. “Kyojuro Rengoku. Do you strongly believe that, with the help of the others, you can remain yourself and refrain from hurting anyone?” He asked softly.

Rengoku bowed to him and answered honestly. “Yes I do! While I was in that state of being a snarling and drooling mess, I didn’t feel angry or aggressive, or as if I was fighting my conscience; rather, I felt as if I was starving and knew that blood wasn’t what I should consume, even if that’s what my brain was wanting. I knew it would most likely corrupt me. When I saw the actual food, I decided to eat it instead. With all honesty, I didn’t intend to rush at Ms. Kanroji so quickly, I was just very focused on eating something other than Sanemi.”

The Master smiled softly and took another moment to think. “Tengen Uzui. You have admitted to holding back when you could’ve very well saved Ms. Kanroji faster, however; I can understand your reasonings. He is your very best and closest friend, this was during a test, and he didn’t seem to jump maliciously. I agree with Ms. Shinobu and think you should have a minor punishment, but you do not have to commit Seppuku. I will decide on the punishment later.”

Tengen repositioned himself as the Master spoke, wanting to be more formal. Once he had finished speaking, Uzui bowed to him with respect. “Thank you, Master. My apologies for my biases, I shall do better if this happens again.”

The Master smiled and nodded happily at Tengen, as a show of acceptance. “It has been made clear, everyone’s thoughts; and I have considered them all. While yes, Rengoku could be a potentially dangerous opponent, now having increased speed and strength; with some training and help, I think he should be just fine. We shall spare him until something, if anything, goes wrong with him.” The Master eventually said. 

A huff of annoyance could be heard from a couple of the Hashira, but overall, mostly everyone seemed relieved. The Master eventually dismissed all the Hashira, and his wife decided to bring Rengoku a new shirt. He put it on immediately and thanked her promptly, then approached Mitsuri, now being in a better mood. 

“My apologies, once again, about your dinner. Perhaps you wouldn’t mind if I got you some more in return?” He asked happily. 

Mitsuri smiled wide and nearly jumped for joy. “You would get dinner with me? Awww!!”

Obanai glared at the Flame Hashira before stepping between him and Mitsuri. “Listen, if she goes, I go.” He demanded, sounding jealous and clearly somewhat upset. 

Rengoku simply smiled and nodded as he let out an amused exhale, then decided to look back at everyone. “I have an idea, why don’t we all have dinner together?” He suggested, as if a few of them hadn’t just voted to kill him off. 

Everyone shared some glances before reluctantly agreeing. Except Tengen and Sanemi. Sanemi blatantly refused and Tengen wasn’t reluctant in the slightest, already at his Best Buddy’s side, ready to go eat something. After saying goodbye to the Master and Sanemi and letting them leave, everyone headed inside the Butterfly Mansion and were eventually all seated at a large table and given plenty of food. Mitsuri and Tengen sat beside Rengoku, Obanai sat beside Mitsuri, and everyone else had random placement. They all ate joyously and talked a bit in between, and overall, it was a good time. It had been a while since all the Hashira had sat down for a meal together, and even though one was missing and everyone was either tired or grumpy, the food helped their mood, and they all felt happier by the time they were full. A couple people, including Giyu, ended up immediately falling asleep once they had stuffed themselves, and eventually had to be carried elsewhere to sleep more comfortably. The others decided to go to their respective residence one by one, and after a while, Tengen and Rengoku were the only ones left at the table. 

“Well, everyone else has either gone home or to bed. You planning on sleeping anytime soon?” Tengen asked with a smile.

“I think I want to bathe first. There’s still a bit of blood on me. After that though, yes; I think I'll head to bed. I feel a bit exhausted.” Rengoku responded with tiredness behind his happy tone.

“Alright, well, I’m patrolling tonight. So I’ll see you some other time. I hope you sleep well, Best Buddy.” Tengen responded happily. 

The two then said their goodbyes for the night and headed their separate ways. Tengen went home briefly then started his patrols, where he proceeded to miss his wives; meanwhile, Rengoku took a long and hot bath before eventually going to sleep in the Butterfly Mansion, because it was closer.

“H-He’s burning up.!” One of them exclaimed with surprise. A second Kakushi checked his pulse and pressed a hand to his chest; their eyes widened. “He’s.! He’s still alive! H-he’s breathing, but just barely!” The young Demon Slayers looked to Rengoku with shock, but were soon ushered away to elsewhere while the rest of the Kakushi focused on the defeated and unconscious Hashira.