Chapter Text
“You’re lying!” Kanao yelled in rage. The Flame Hashira had already rushed ahead to secure Aoi in a cell, and Inosuke was carrying Shinobu to get medical care. This left Kanao alone to watch over Muzan, who was still drained from Kanae’s Blood Demon Art. With Tanjiro’s body too heavy for her to carry, they had to walk back.
“I have nothing to gain from lying to you,” Muzan responded. He still had enough strength to walk. Kanao knew who he was now, so there was no point in hiding anything.
“You got millions of people killed just to find some stupid flowers,” Kanao said in disbelief. The blue spider lily was the only thing Muzan needed to become utterly immune to the sun.
“Yes, with that, I would become utterly immortal and invincible. If I were still in my actual body,” Muzan admitted. He felt a small sense of relief that Tanjiro didn’t know where those flowers were.
“So everyone is living in hell because instead of going to a flower shop, you decided to create an army of evil demons to kill innocent people,” Kanao remarked, her voice filled with disgust.
“Trust me, if you could make an army of demons, you would.”
“No! I would never create an army of evil demons, ever! Knowing that one of them ended up killing my sisters’ parents right in front of them,” Kanao shot back.
“You do realize that if that hadn’t happened, those sisters would never have adopted you. You’re welcome,” Muzan responded, snapping his fingers and pointing at her.
“So are you going to ask?”
“You out on a date? If you inflate your breast a little more maybe.”
“Asked me where to find those flowers.”
“Nope, I’m too good to ask humans for help finding those flowers”
“So you rather create an army of demons that are only interested in killing and eating humans than ask for help from the only species that manage to locate the blue flowers.”
“Yes.”
“You’re stupid.”
“I prefer poorly written.”
“I have no reason not to kill you right now.”
“My family will never believe that the 1000-year-old Demon King was their eldest son and brother the entire time and that the real Tanjiro disowned them all just to play around in my body.”
“Every person that was killed because of you deserves justice,” Kanao declared, but Muzan had heard this countless times over the millennia.
“Yes, and what about everyone your boyfriend has killed and kidnapped?” Muzan countered.
“What are you talking about?” Kanao asked, her anger momentarily replaced by confusion.
“Muzan Kibutsuji is my true love. No one can understand him as I do. My heart is with him, my love is with him, and he is the one.” Muzan mocked, causing Kanao to go red in embarrassment.
“What are you talking about?” Kanao lied, her heart aching at the truth. She had fallen in love with Tanjiro, who had been trapped in Muzan’s body for years.
“So, how did my lips taste? A kiss from a supreme being--sure, that brat is in it right now, but it's still my lips.” Muzan continued to taunt.
“Shut up! He groomed me. He was just a disgusting predator.”
“Not really, since you are older than him,” Muzan replied nonchalantly.
“You're right. He was young when he impersonated Amane and turned everyone's lives into a living hell. Why?”
“Don’t know. He woke up in my body and later decided he wanted to stay. Then he slept with my cousin.”
“Cousin?” Kanao looked at Muzan, confused.
“The Ubuyashiki family is descended from my cousin. I never told anyone because I never thought some dumbass would end up in my body and make love to my cousin with my body,” Muzan said in frustration.
“It must have been Daki’s idea. I’m killing that bitch when I get my body back. No, I’m killing her in this body. I still need to prove that my demon breathing is better than that pebble breathing,” Muzan said, determined to fulfill one of his lesser goals.
“You really care about that?” Kanao asked, incredulous.
“Yes, I created demon breathing, so it needs to be the best of them all. I need to go to the swordsmith village to get new gauntlets.”
“Wow, you’re petty.”
“I need to be strong for my family.”
“Don’t you mean Tanjiro’s family?”
“No, my family.” Muzan’s eyes hardened. “I have to be strong for them. Even if the Kamado gang no longer exists, they still see me as their light and savior. Their love and worship are the closest things I have to being a near-perfect being. I can’t let them believe for even a moment that they were wrong to trust me.”
“But you're not actually related to them.”
“You aren’t related to Shinobu or Kanae, but you still call them your sisters. Besides, this body is related to them, and I’ve been in this body for five years now.”
“So, you care about them?” Kanao asked, trying to understand.
“I would be dead right now if it weren't for them. All I had when I woke up in this body was that family,” Muzan said, a rare moment of sincerity in his voice. He thought back to the Kamado family, remembering how he had attacked Nezuko the moment he woke up. Yet, Nezuko had forgiven him without even asking why. Of all the families he had in his long life, the Kamado family was his favorite.
“I’ve had families before, Kanao, and unlike all the ones I had before, I will never get bored of them or have any desire to eat them.”
“Still an evil asshole,” Kanao muttered.
“Pretty sure I’m less evil than the guy who set up Mitsuri to be tortured,” Muzan retorted. He never knew the details about Mitsuri's torture until Shinobu’s rant. Tanjiro had gone out of his way to ensure everyone was enraged by making Mitsuri brag about her engagement to the person who ruined all of their lives.
“Tanjiro wanted Mitsuri to suffer. Why?” Kanao asked, the memory of that event still fresh in her mind. She wasn’t there during Mitsuri’s sentencing, so she thought Mitsuri had only been yelled at and hit a few times. She never imagined that Shinobu was capable of mutilating another human.
“You were there when Kanae disowned her sister, broke her arm, and stated that the snot brat was a better Demon Lord than me,” Muzan explained. “Tanjiro woke up surrounded by people loyal to Muzan, not him, so he needed to change that.”
“So that’s why the mass abduction happened? Why did he make me fall in love with him?”
“He wanted power over you,” Muzan said flatly, causing Kanao to reel in disgust. “Don’t forget, he’s still a teenager. He didn’t need to sleep with Mitsuri, but he was a naughty, horny boy.”
“He’s… worse than you. You're just an evil scumbag who’s too stupid to go to a flower shop. He planned everything out, kidnapped Kanae, turned her into a demon, and manipulated everything to make Kanae want to kill her own sister,” Kanao said, her voice trembling with anger.
“Unlike me, you’ve met and talked to him. What exactly is his end goal anyway?”
“He said he wants to kill all bad people. Then he tried to turn me into a serial killer,” Kanao replied.
“A brat with the power of a god who wants to kill all the boogeymen. He really is a brat.”
“Who thought putting him in a human body was a good idea? Everyone is going through hell because of the mind-swapped demon.”
“I don’t know.”
“Hold on! I thought you could hear the thoughts of all demons. How did that mind-swapped demon ever get close to you to make the switch?”
“I’ve been asking the same question for five years now. I’ve also been asking why Tanjiro, of all people.”
“That demon has to have done it before,” Kanao theorized. “The mind-swapped demon had to know how powerful you were and only had one chance to pull it off. There have to be people around that he practiced on.”
“That demon eats them. It would be important that no one ever finds out a power like that was real.”
“Why did the mind-swapped demon not kill you? It’s still a demon after all.”
“I wish I knew. Tamayo was the only demon that escaped my control, and that was only because of Yoriichi.”
“So the mind-swapped demon was under your command but also escaped because of this Yorrichi thing.”
“Yorrichi was a person, not a thing. I guess the closest thing to a Yorrichi in this era would have been my dad,” Muzan stated. No doubt that somehow the mind-swapped demon escaped Muzan's control before its blood demon art was even known to it. That demon had to be cut off from Muzan only days after it was turned into a demon.
“It would actually make sense for the mind-swapped demon to know Tanjiro’s dad. It took his family heirloom and gave it to his son.”
“Wait, wouldn’t that mean that Mom knows about the mind-swapped demon?” Muzan asked. If the father knew about the mind-swapped demon, then there would be no way that he would have never once mentioned it. But if he knew about the mind-swapped demon, why would he not use the mind-swapped blood demon art to save himself?
“No, if Dad knew about the mind-swapped demon, then he would have used him to save himself. Maybe he never knew it was even a demon.”
“So, from what we know so far about the mind-swapped demon, it became a demon, and the first thing it did was break free from its control. I bet you don’t even remember turning a person into the mind-swapped demon.”
“I don’t think it was me that created a mind-swapped demon. I was also trying to make a demon that was immune to the sun, so I made sure I knew was its blood demon art before I forgot about them.”
“So, was it your Upper Moons?”
“They need my approval first, or else I kill the demon they try to create.”
“You think the mind-swapped demon turned itself into a demon without you knowing.”
“That’s physically impossible. Only people with my blood in them become demons,” Muzan stated, but Kanao suddenly froze. Something in her mind just connected. She looked at both of her hands, put them together, and ended up concluding.
“Muzan, how did Kagaya know about the switch?” Kanao asked.
“I don’t know. There’s something magical about that family.” Muzan never understood how they managed to avoid him for so long and how they even became aware of the switch. Muzan knew to rely on Hanako to fully understand everything about that family.
“Yes, your blood in their veins. Doesn’t that mean they could turn themselves into demons without you knowing?”
“They would have done that a millennia ago. And Kagaya is still a human dying from a terminal illness. Plus, they would need the blue spider lily to become a demon without me. How could they even find that flower?”
“In a flower shop, dumbass.”
“You’re going full into the mind-swapped demon being a long-lost Ubuyashiki. If what you’re saying is true, then why not put a fellow Ubuyashiki in my body instead of a brat?”
“Because it’s a demon. It would get killed the second it gets near the home of the demon slayers.”
“So, hypothetically, if what you’re saying is true, what can we do about it? Mitsuri is a prime example of what Kagaya does to people that piss him off. Plus, Tanjiro is still a problem, and we need to deal with the issue that’s right in front of us.”
“What?”
“How to prevent Shinobu from jumping from a very high place,” Muzan asked with concern. To have her older sister dishonor her and disown her had to be utterly devastating for Shinobu.
“She won’t do that. She’s not that stupid. There is a family that relies on her and loves her.”
“Yes, normally she is knowledgeable, but when she’s in distress. She tends to do things like cut off a finger, hide a body, and rant about how much Mitsuri needed to have her fingers cut off. Kanao, how would you react if Shinobu said ‘you’re dead to me’ right to your face?” Muzan asked.
"I... I don't know," Kanao admitted. She couldn’t even imagine Shinobu saying that to her. She also could not imagine Shinobu justifying torture. Everything felt wrong, like everything and everyone was misplaced.
They were quiet the rest of the way home, the thought of Kanae and Shinobu’s fallout lingering in their minds. Everything had gone so wrong so fast. Getting Kanae her memory back turned out to be the worst possible choice, as it now left them with a potent foe.
"Welp, I'm going to bed. You should make sure that Shinobu doesn't drink her poison," Muzan stated.
"She won't do that," Kanao said, but her voice carried a hint of worry. She left to find Shinobu, leaving Muzan to walk back to the Butterfly Estate alone. He entered the home and felt like there was no one there.
"Where is everyone?" Muzan asked himself. Kie, Hanako, Rokuta--there was no one in the house. Muzan thought about what could have happened, but his mind drifted to the fastest way to get to bed. He still longed to have everything that the mind demon had taken from him.
He walked to his room--well, not really his room, just a room that Shinobu was letting him sleep in. She had been there when Kanae outed him as Muzan, but she also disowned her and broke her arms, so Muzan was likely the last thing on her mind at the moment.
He thought about everything that had happened in a day: Kanae’s letter, Takeo's secret best friend, and the fallout between the sisters. So much drama, and he had been dragged right into the middle of it. Muzan hated drama. He missed the days when he could just kill anything that annoyed him and move on.
He entered his room, reflecting on the blunder of his first mission as a demon slayer. He knew that his sister had her first mission as a demon slayer, and Muzan was sure she was having a blast not dealing with all this drama. He wanted to crash into the bed, but something moved.
"You picked a bad time to rob a house," Muzan muttered, his voice laced with the anticipation of violence. At least he could beat something to death and eat the corpse, just like in the glory days. "Just so you know, I'm not above cannibalism."
"No, it’s me," Kiriya’s voice came from the supposed robber. It wasn't a robber--it was Kiriya. Kiriya was utterly alone in his bed. He hadn’t left the house since Muzan had gone to kill Kanae. Muzan knew that Hanako was nowhere in sight. He remembered that Kanao had mentioned Kiriya had known about the swap for a very long time, to the point where he no longer tried to hide that he knew.
"Let me guess--you told Hanako about your condition, and she didn’t take it well," Muzan said, exhaling in frustration. It seemed that he had escaped one drama involving Hanako and Kiriya only to run into the Kanae and Shinobu drama. No matter where he went, there was nothing but drama.
"Yes, I told her," Kiriya began, his voice shaky. "First, I told her that I would become utterly blind in 10 years. She was fine with that, so I told her that a couple of years later, I would be dead. She thought I was joking and lying." Kiriya rubbed the cursed mark on the corner of his forehead, the reminder of his fate.
"She went into complete denial," Muzan said, sitting beside Kiriya and pulling him close into a comforting hug. It struck Muzan as odd that Kiriya, his cousin, was now in a similar position to the Kamado siblings, who were also tied to him in complicated ways. Tanjiro was the eldest sibling of the Kamados, and Kiriya, despite his illness, was also Muzan's kin.
"Hanako has been visiting your home every day for nearly two years, and the curse was never once mentioned?"
"No," Kiriya sniffled, wiping away a tear. "Every single person I ever met knew about the Ubuyashiki curse before I did. So I ended up believing that Hanako also knew about the curse. It was only today that I realized no one had ever told her."
The Ubuyashiki curse--a mysterious, deadly affliction--killed every male member of the family. Muzan had never cared about the curse or the family until now. He wondered how it worked. He knew it was because they were related to him, but that explanation felt insufficient. Why was one family punished for being related to a person they never even met?
"Why is your family being punished for something I did?" Muzan asked, his tone tinged with confusion and frustration. "I never knew I even had a cousin until those demon slayers raided my home and killed my parents."
"Killed your parents? What are you talking about?"
"Kanao told me that you already know who I am. You were never told how the first Ubuyashiki, my cousin, killed my parents?"
"No? Honestly, I never knew that you even had any parents," Kiriya replied, curiosity evident in his voice. Muzan saw no fear in the small boy. It made sense; the only memory Kiriya had of Muzan Kibutsuji was the former demon lord saving his life and the life of his sister.
"Well, I became a demon. My mom and dad soon learned that I could only live by eating other humans, so they fed me other humans," Muzan explained. He hadn’t thought about his parents' actions for millennia. They loved him so much that they became serial killers just for him, and he had been too selfish and self-centered to care.
"So creating demons to kill innocent people was their idea?" Kiriya asked, his tone innocent yet probing. Muzan thought about how love could drive people to do evil things. When Kanao confessed to Shinobu that she had killed someone, Shinobu’s first reaction was to hide and destroy all evidence of it. Love was such a strange and powerful force.
"No, that came much later," Muzan admitted. "I wish I had been nicer to them. They sacrificed so many lives for me, and I never even considered saying so much as a thank you. I didn’t deserve them." His voice was heavy with regret. His parents had been so loving to him, yet he hadn’t cared. He hadn’t even bothered to bury them when they were killed--he had only seen their corpses as something to eat.
Muzan listened as Kiriya pieced together the tragic history of their intertwined families, his young mind trying to make sense of a century-old curse and the twisted legacy it had left behind.
"So, the reason why you’ve been an evil person for 1,000 years was that you had horrible parents who fed people to you like a dog," Kiriya said, his voice filled with a mix of horror and curiosity. "Did the first Ubuyashiki kill them because those parents killed his parents?"
"Yup," Muzan replied, his tone flat. "My grandfather was rich, and my father wanted all of his money to himself. So he fed me my grandfather, my grandmother, my uncle, my uncle’s wife, and my niece. Somehow, my cousin got away."
Kiriya frowned as he processed the information. "So, the first Ubuyashiki got revenge by gathering all of the friends and family members of the people that were fed to you and killed your parents," he concluded, his sharp mind working quickly.
"Yes," Muzan confirmed. "That’s when the demon slayers were founded." He remembered the carnage vividly--the rivers of blood, the fear in his parents' eyes, and the thrill of his newfound power. It was the first time he had discovered that he could morph his body into anything he wanted. He was the only one left alive in that house, a twisted remnant of his family's greed and ambition.
"So why is my family cursed?" Kiriya asked, his voice tinged with a childlike innocence that contrasted with the heavy topic.
Muzan sighed, admitting, "I don’t know. I spent centuries indulging myself and searching for the Blue Spider Lily. I don’t even know if the curse is because of my body or my soul, and those two things have been separated now."
"After my family was killed, I ended up creating my first demons to replace them," Muzan continued, reflecting on his past. "But they weren’t like my parents, so I made more and more. That’s when the demon epidemic began. I think your family is being punished because the first Ubuyashiki didn’t just go to the local guards or authorities."
Kiriya shook his head, trying to grasp the reasoning. "That doesn’t make any sense. If he had gone to the guards, they would have gotten killed anyway."
"I’m just guessing, some god was like 'You know what, that guy is a jerk, so I'm going to punish a family that has nothing to do with him with a fatal curse.'" Muzan admitted, his voice heavy with frustration. "You’re going to die young just because you’re related to some asshole. And I’m not even that asshole anymore--Tanjiro is the new demon lord."
The room fell into a somber silence as the weight of their shared history pressed down on them. Muzan couldn’t help but wonder if Tanjiro, now in possession of his powers, knew about the curse. He had spent a year acting like Amane, the Ubuyashiki family matriarch. Surely, he would want to save Kiriya, maybe even by turning him into a demon, like how he saved Tamayo.
Muzan broke the silence with a question that startled Kiriya. "Did you know a person named Tamayo?"
"Yes," Kiriya replied, his eyes narrowing. "That fake mother hired her as my father’s doctor. She ran several tests on my dad and me. She claimed she was trying to cure our curse. She ended up taking buckets full of our blood and fleeing to do who knows what with them."
Kiriya shuddered at the memory, tightly gripping his arms as he recalled the countless needles Tamayo had used, and the medican they took. "She said she wanted to cure us, but all she did was take our blood and disappear."
Muzan felt a pang of anger. Tamayo had betrayed him too, though in a different way. She had once been his most loyal servant before turning against him and fleeing. Now, it seemed she had also betrayed Kiriya, giving him false hope of a cure.
"She was always good at lying," Muzan said bitterly. "But don’t worry, Kiriya. I’ll find a way to protect you from all of this."
Muzan vowed to himself that he would do whatever it took to break the curse, to free Kiriya from the fate that had claimed so many of their ancestors. For the first time in centuries, Muzan felt a genuine sense of responsibility--an unfamiliar, but not unwelcome, sensation.
Muzan listened intently as Kiriya vented his frustrations and pain. The conversation had taken a dark turn, revealing the deep-seated anger and confusion that Kiriya harbored. Muzan could see that his cousin was struggling to process the complex web of emotions tied to the recent events--the betrayal, the revenge, the suffering, and the twisted justice that had been meted out.
"Are the new demons being created with you and your dad’s blood?" Muzan asked, curious about the origins of the demons and the purpose behind Tamayo’s actions. It didn’t make sense to him that she would need their blood when she already had access to his own, far more potent supply.
Kiriya’s response was raw and emotional. "I hate them, I hate both of them," he cried, his small body trembling with the weight of his emotions. Muzan pulled him into a tight hug, offering a rare moment of comfort. He could understand Kiriya’s pain--betrayal and hatred were feelings Muzan was intimately familiar with.
"You want to vent out your frustration by torturing one of your slaves?" Muzan suggested, remembering how Mitsuri had been tortured and how it had seemed like an outlet for the family's rage. He wondered if this could help Kiriya channel his anger.
But Kiriya shook his head, his voice breaking. "Muzan, we don’t own slaves, and we don’t torture people for fun."
Muzan raised an eyebrow, surprised. "Where were you when Shinobu was cutting off Mitsuri’s fingers?" he asked, recalling the brutal scene. To Muzan, it had seemed like a necessary act of revenge, but Kiriya’s reaction suggested otherwise.
"I was right next to Mom and my sisters," Kiriya replied, his voice heavy with the memory. The entire family had witnessed the torture, and the sheer intensity of their hatred had left a lasting impact on him.
Muzan sighed, trying to explain his perspective. "Kiriya, I was alive for over 1,000 years. I know that the line between justice and revenge can get blurry. But I know that the only people who torture others are sad*sts and those filled with pure hatred. What you all did to Mitsuri was revenge, I’m sure what she did was out of stupidity, not malice."
Kiriya looked up at Muzan, his eyes filled with pain and confusion. "If only you were there, you would have understood. People committed suicide, Muzan. I had friends who were kidnapped. That day, when everyone was screaming and crying for their loved ones, and all we could do was hear them, it was hell. Everyone was suffering so much, and that pink girl came in with pure blissful joy. She even showed up with the wedding ring that Muzan----stole from my mom."
Muzan frowned, absorbing Kiriya's words. The devastation that Tanjiro, in his body, had caused was immense, far greater than Muzan had realized. "Don’t you mean Tanjiro?" he asked gently, trying to steer the conversation back to the truth.
"Yes, Tanjiro," Kiriya confirmed, his voice filled with bitterness. "Things were better off when you were the demon lord."
"Are you marrying his little sister just to get back at him?"
Kiriya shook his head. "No, Muzan. His family isn’t even aware of the switch. Your spy, Hanako, is just an innocent girl."
Muzan’s eyes widened in surprise. "Spy?"
Kiriya chuckled softly. "We’re not stupid. We know that you sent Hanako to spy on us."
But Muzan quickly corrected him. "No, I sent her to marry into that rich family."
“Right, we’re rich now, the elite of society, top one percent. With hundreds of people working for us. All because Tanjiro pretended to be my mom for a year while my actual mom was locked in a basem*nt. Screw him!”
“I know. I’m better than that toddler and in every imaginable way, I’m even a better older brother than the brat. Right little brother. Muzan said while petting Kiriya.
“Right, Muzan Kibutsuji is going to be my big brother. How the hell has everything become so twisted.” Kiriya asked.
“Everything changed when the mind swapped demon attack, or whatever caused the switch. On the bright side, you would have never met the love of your life.”
“We argued and yelled horrible things at each other, things went wrong so fast that we ended up pushing and hitting each other, and Kie had to break us up. She ran away screaming I hate you, I don’t think she wants to marry me anymore.” Kiriya said.
Muzan listened to Kiriya's words, noting the deep concern in his voice. "Kiriya, emotions can get the best of us sometimes, especially when everything feels like it's falling apart," Muzan said, his voice unusually gentle. "But that doesn't mean it's the end. People say things in the heat of the moment that they don’t mean. You and Hanako have been through a lot, and that kind of stress can push people to their limits."
Kiriya sighed, his shoulders slumping. "But what if she really hates me now? What if I’ve lost her for good?"
Muzan shook his head. "It’s not over just because of one fight. If anything, this is a chance to show her how much she means to you. You’ve got to apologize, but more than that, you have to show her that you’re willing to work things out. Relationships aren’t easy, and they take effort. But if you really care about her, you won’t let one argument ruin everything."
Kiriya looked up at Muzan, uncertainty in his eyes. "But what if she doesn’t forgive me?"
"Then you keep trying," Muzan replied firmly. "You don’t give up on someone you care about just because things get tough. You find a way to make it right. And if you’re honest and sincere, chances are she’ll see that."
Kiriya nodded, a small glimmer of hope returning to his expression. "I’ll try. I just don’t want to lose her."
Muzan gave him a reassuring pat on the back. "You won’t, not if you’re willing to fight for her. Just remember, you’re not alone in this. You’ve got family, even if it’s a weird, messed-up one like ours."
Kiriya managed a faint smile, appreciating the rare moment of kindness from Muzan. "Thanks, Muzan. I’ll figure it out."
"You better," Muzan said with a smirk. "I’m not going to let my little brother screw up his love life without a fight.”
“Ok, big brother. Kiriya hugged Muzan again and ran off, it was odd for Muzan to have a Ubuyashiki fully trusting him and loving him as a brother but he did not hate it. Tanjiro would had no reason to hate it and that was who he was playing for half a decade now.
Muzan, settling into the role of Tanjiro, felt an unexpected satisfaction in being the older brother. It was a new experience for him, one that came with a sense of responsibility and affection that he hadn’t anticipated. The idea that Tanjiro had willingly given up this role, choosing instead to become the demon lord, seemed utterly foolish to him. In Muzan’s mind, Tanjiro had made a grave mistake--one that would likely cost him his life once the switch was reversed.
As Muzan thought about what might happen when he returned to his own body, he felt a mixture of uncertainty and indifference. The bond he was forming with Tanjiro’s family was something he hadn’t expected, and while it intrigued him, it also complicated things. Would he continue to care for them, or would he revert to his old ways? The answer eluded him, and for now, he was content to let the question linger in the back of his mind.
Pushing aside these thoughts, Muzan allowed himself to drift into sleep. For now, he was Tanjiro, the older brother, and that was enough. Tomorrow would bring its own challenges, but for the moment, he was at peace with the role he had taken on.
