Akaza stands in the entrance to the Infinity Castle after being summoned their by Nakime, one of Muzan's most loyal demons. He looks around, looking for any sign of movement from other demons within the castle, yet nothing reveals itself.

This place is... the Infinity Castle. Being summoned here only means one thing. The ranks of the upper Twelve Kizuki has changed. An upper moon kizuki has been killed by the demon slayers.

Akaza says to himself as he starts to wonder who has been slaughtered by the ranks of the demon slayers. Akaza puts his arms out straight as he falls forwards, free falling down, knowing the positioning of the rooms could change at any moment. The ground below him splits as he ends up outside, looking down at the so called dimension that can't be seen by the human eye. He looks at the clear water below him, the wildlife lit of by the moonlight, the orange candle light, lighting up the windows of the infinity castle. He is brought back inside again as he continues to fall. He flips forwards as he lands on the ground, punching the ground as he lands in order to balance himself. He stands up as a column pushes him from the back, bringing him forward and then up into the air once again. He looks upwards as multiple doors open, bringing him into a wide space where black columns of wood hang from the rooftop.

There is the sound of a Biwa being strummed once as he is brought into a wide open room with many different doorways to new rooms. He looks around and spots Nakime sitting on a floor just above him, her long black hair covering her eyes, a biwa laid across her lap, her pic in hand, ready to strike the biwa once again.

"Hyo!" an echoed voice says from Akaza's side as he looks over and sees a white vase with a floral pattern painted all over sitting there as it jumps slightly, "well, well, if it isn't you, Lord Akaza!" the voice says as four small hands rest over the side of the vase's opening, "so lovely to see you in such good health!" the upper moon five, Gyokko, says as he pulls himself out of his pot, his eyes where his mouth would be, another on his forehead, two sets of lips where his eyes should be, "what has it been, ninety years? The thought that you might have perished made my heart sing-- it made my worried heart fill with anguish!".

"Terrifying! Terrifying!" a trembling voice says from nearby as Akaza and Gyokko look over, managing to make out the upper moon four, Hantengu's, cowering figure from behind the staircase, "in the time we have been apart, you have forgotten how to count, Gyokko. It has been one hundred and thirteen years since we were last summoned. An indivisible number... unlucky and uneven... an odd number! Terrifying! Terrifying!".

"Biwa woman!" Akaza says as he looks at Nakime, completely ignoring Gyokko and Hantengu's bickering, "is Lord Muzan not here?".

"He has not yet arrived" Nakime says calmly as she strums her Biwa.

"Then, where's the Upper One's?" Akaza asks as he turns his entire body to look at Nakime, "don't tell me one of them has been killed".

"Woah, woah, woah!" a voice says from the distance as the flames in the candles on a nearby staircase turn from orange to blue, "hold up a second, won't you, Lord Akaza" the voice says as it gets closer to Akaza, "aren't you even a little bit worried about me?" the upper moon two, Douma, says as he places his hand on Akaza's shoulder, "you don't know how dreadfully worried I was, since you all are cherished comrades of mine! And I'd be so heartbroken if I lost any of my precious comrades".

"Hyo! Lord Douma!" Gyokko says as he leans forwards out of his pot slightly.

"Hey there!" Douma says as he waves at Gyokko, "long time no see, Gyokko! Is that a brand new pot? It's a beauty! You know the pot you gave me? I'm displaying a woman's head in it! In my room".

"That wasn't it's intended use" Gyokko says as he looks at Douma, "but I do find it intriguing!".

"Listen! You should come over to my place sometime" Douma says happily.

"Get off" Akaza says calmly.

"Huh?" Douma says as he looks at Akaza.

"Get your hand off of me!" Akaza says angrily as he punches the bottom half of Douma's face off.

Blood splatters onto the tatami mats as Hantengu shrieks, grabbing the top of his head as he cowers again.

"Woah!" Douma says as he quickly heals the injury, "wow, that was some punch. A bit stronger than before, would you say, Lord Akaza?".

"I summoned Upper One here first" Nakime reveals calmly, "even now, he is listening to us".

Akaza gasps as he looks down and sees one of the upper one's, Kokushibo, sitting at a table, drinking some tea.

"I've been here the entire time" Kokushibo says as he doesn't look at them, "the second upper one has not yet arrived".

Just as Kokushibo says that, they hear a distant screaming from above them. They all look up and see Sakura falling. She lands on the ground, face first as she lies there.

"Nakime, is everyone here?" Sakura asks as she doesn't get up.

"Apart from Lord Muzan, yes. Everyone is here" Nakime says as she looks at Sakura.

"Nakime. I was eating Aoi-chan's udon" Sakura says as she gets up, looking at Nakime, her injuries back to normal, "do you know how good Aoi-chan's udon is?".

Nakime strums her biwa as Sakura holds the udon in her hands, chopsticks there and everything. Sakura smiles as she sits cross-legged on the ground as she happily eats her udon.

"Ah, I am so happy that being a demon didn't mean I lost my appetite for human food" Sakura says as she shuts her eyes, "bet you're all jealous. You should be. Aoi-chan's udon is the best. Oh, and by the way, Muzan's here".

There is the sound of a drop of water as everyone apart from Sakura and Kokushibo look up and see Muzan above them, doing his little experiments.

"Gyutaro is no longer with us" Muzan says as he holds a test tube in his hand, all of the demons getting on their knees, apart from Sakura who happily slurps her udon, "meaning the ranks of the Upper Moons are incomplete".

"Is that true, my Lord?" Douma asks as he looks up at Muzan, "you have my sincerest apologies! Since I was the one who brought Gyutaro in. How can I atone for this embarrassment? Shall I... gouge out my eyeballs? Or should I--".

"I have no need for your wretched eyeballs" Muzan says as he glares at Douma, "I knew that Gyutaro would be defeated. As expected, Daki proved to be his weakness. Had Gyutaro fought alone from the start, he would have won. If the battle hadn't gone on after he'd poisoned them. Oh well. It doesn't matter anymore. How worthless. Can't you see that you are falling in order of who has the most of their humanity remaining? But neither does that matter anymore. I expect nothing of you all".

"You've gotta hand it to the demon slayers, Muzan. They're good" Sakura says, her mouth full of udon.

"There you go again with those melancholic words" Douma says as he looks down, "has there ever been a time when I didn't meet your expectations?".

"You still haven't annihilated the Ubuyashiki family" Muzan says as he starts to list everything the demons haven't achieved, "what about the Blue Spider Lily? Why can't you find it after so many hundreds of years? I'm... starting to question why any of you exist".

"Oh, please forgive us. I beg of you!" Hantengu says as he becomes more worried.

"I don't know what to tell you" Kokushibo says calmly, "Ubuyashiki... is a master at sealing himself".

"Search and detection isn't my strong suit, either" Douma says as he sways side to side, "I'm at my wits' end".

"Lord Muzan! Not me!" Gyokko says as he looks up at Muzan, "I've acquired some information that will bring you a step closer to your goals! A mere moment ago--".

"The one thing I dislike is change" Muzan says as he tears Gyokko's head from his neck, holding it in his hand, "changes in circumstances. Physical changes. Emotional changes. In most cases, changes of any kind mean degradation. It's decay. I prefer the unchanging. A perfect unchanging state that lasts forever".

Ah! To have Lord Muzan's hand on my head. How sublime!

Gyokko says as he starts to blush.

"For the first time in one hundred and thirteen years, an upper moon has been killed" Muzan says as he holds his forehead, "and my frustration has reached beyond boiling point. Don't ever give me unconfirmed information! And wipe that smirk off of your face!".

Nakime strums her biwa as Gyokko's head lands on the ground right next to his body.

"I'd advise you all to apply yourselves with more desperate urgency from now on" Muzan says as he looks down at them all, "I've been far too lenient, considering your failures... all because of your status as Upper Ranks. Gyokko, once you've confirmed that information, head over there with Hantengu".

"Understood, my Lord!" Hantengu says as Muzan disappears.

That's hardly fair! I found that information myself in the first place! How annoying is that!? But that's what makes it intriguing!

Gyokko says as he picks himself up from the floor, using his arms to hold him up.

"Huh?" Gyokko says as a shadow is cast over him.

"Lord Gyokko!" Douma says as he looks down at Gyokko, "what kind of information do you have? I'd like to tag along!".

"No, that wouldn't be..." Gyokko says as he looks at Douma.

"Can't you let me in on it? Please, I'm begging--" Douma says as Akaza walks over and punches the top of his head off.

"Did Lord Muzan give you any orders?" Akaza asks as he looks down at Douma, "get lost".

Akaza's wrists are cut off as he looks at both his missing limbs.

"Akaza... you always go too far" Kokushibo says as he walks past Akaza.

"I just wanted to cut you cos it's fun" Sakura says as she puts her sword back.

"It's alright, Lord Kokushibo, Lord Sakura" Douma says as he heals his head, "I don't mind in the least".

"It's not for your benefit that I speak" Kokushibo says as he puts his sword away, "disrupting the hierarchy... which, in turn, undermines subordination. That's what dismays me".

"Oh, is that right? I see" Douma says as he does a peace sign.

"Akaza... if you're disgruntled, you should battle for a replacement" Kokushibo says as he looks forward.

"Well, well, if I may, Lord Kokushibo?" Douma says as he crawls over to Akaza, Kokushibo and Sakura, "even if he were to challenge us, Lord Akaza could never defeat us. And in my case, since I became a demon after Lord Akaza... yet was promoted before him, I'd be angry, too, if I were in his shoes. Don't be so hard on him! And besides, I didn't dodge that blow on purpose. It's just a little harmless horseplay! This is how you nurture friendship, you know? Those of us on top shouldn't give our subordinates a hard time. Don't you think--".

"Akaza!" Kokushibo says as he looks at Akaza, "do you understand... what it is... I'm trying to say?".

"I understand" Akaza says as he looks at Kokushibo, "I'm going to kill you and Sakura first".

"Pfft! Haha!" Sakura says as Nakime strums her biwa, "good luck with that one!".

"No, Lord Sakura, don't go! I was gonna invite you for some drinks!" Douma says disappointedly.

"Is that right? Then do your best" Kokushibo says as he disappears.

"Goodbye, Lord Kokushibo!" Douma says as he looks at where Kokushibo was, "goodbye! It kind of feels like I got left out of the conversation. But that's just me overthinking it, right, Lord Akaza?".

Akaza balls his fists as he jumps upwards, leaving the castle.

"Lord Akaza!" Douma shouts as he watches Akaza, "hey, I was talking to you. Huh?".

"Biwa woman!" Gyokko says as he walks out from behind Douma, "please send Hantengu and myself to the same place!".

With two strums of her biwa, Nakime sends Hantengu and Gyokko away.

"Wait a minute. I'll go too!" Douma says as he points to himself, "hey! Biwa woman over there! If you were interested, would you like to join me for--?".

"I respectfully decline" Nakime says as she sends Douma back to where he was.

--- at the butterfly mansion ---

"Ahh, you're back!" Kiyo shouts as Sakura comes back into the bed she was sitting in.

"I'm sorry for scaring you" Sakura says with a smile, "I was summoned to that place again".

"Did they do anything to you? Are you okay?" Naho asks as she looks Sakura up and down.

"They didn't do anything to me, don't worry" Sakura says as she ruffles Naho's hair, "I even got to finish Aoi-chan's udon".

"Sakura-sama, Sakura-sama!" one of Ubuyashiki's private Kakushi says as they run into the room.

"Whatever's the matter?" Sakura asks as she looks at the person.

"It's Master Ubuyashiki. His pain is becoming worse!" the Kakushi says worriedly.

"Girls. Let Shinobu know I've left for a few hours" Sakura says as she rushes out of bed.

"We will!" Sumi says as the three of them watch Sakura rush out of the room with the Kakushi.

--- in Tanjiro's dream ---

"I've brought some tea for you" Sumiyoshi, one of Tanjiro's ancestors says as he walks over to a man with long red hair.

"Right. Thank you" the man says calmly.

"Look how soundly he's sleeping" Sumiyoshi says as he looks at his son who sleeps peacefully in the man's arms, "I'm sorry about this. It looks like my wife is fast asleep, too. I really must apologise. Making our guest babysit like this. Speaking of which, where is your wife?".

"She went out to go fetch you some water. She spotted that your wife is running a bit of a fever" the man says as he smiles at Sumiyoshi's son, "but fear not. My wife is a doctor and says that she will be fine with some soup she'll make her. And there's no need to apologise, either. Your wife is obviously exhausted. It's a lot of hard work, giving birth to a child and then raising them. We'll be leaving once my wife has cooked up the soup for your wife. It wouldn't be right for the two of us to keep eating and sleeping here for free. We have our home to get back to".

"Don't say that!" Sumiyoshi says as he puts the tray down, taking his son from the man, "you and your wife saved our lives! If it hadn't have been for the two of you, not only would we be dead, but this child would not have been born, either. Very well then. Then the least I can do is to pass down your name to posterity".

"No need for that" the man says as he picks up a cup of tea and drinks it.

"But didn't you say you were at a loss because you have no heirs?" Sumiyoshi says as he looks at the man, "your wife told us about her story. How she'd been turned into a demon a few years ago? She can no longer have children. It must be tough. Even if a humble charcoal seller like myself can't do it, I'm sure that one day, somebody will".

"No need for that" the man says as he puts his cup back down on the tray, "Sumiyoshi. Those who have mastered their skill... share the same fate. Even if it's a new era. Even if you must take a different path to get there, you'll always find your way back to the same place. You seem to perceive my wife and I as special people, but you're wrong about that. I failed to protect anything that was important to me, and throughout my life, I was unable to do anything I was supposed to do. My name is as worthless as I am".

Please don't. Please don't say something like that. Please, I'm begging you! Don't think of yourself like that!

--- in the butterfly mansion ---

"So sad" Tanjiro says as he starts to wake up, tears brimming his eyes, "so sad. It... was a dream".

Kanao opens the door after refreshing Tanjiro's flowers when she sees Tanjiro awake. She gasps as she drops the vase, the vase shattering, water spilling all over the floor.

"Where... am I?" Tanjiro asks as he lies there.

"Are you okay?" Kanao asks as she runs over to the bed, "you've been in a coma for two months ever since that battle!".

"Is that right?" Tanjiro asks as he looks at Kanao, "I see".

"I'm so glad you woke up!" Kanao says as she starts to tear up.

Goto, one of the Kakushi walks into the room with a plate of castella when he sees the broken vase on the ground. He looks over and sees Kanao next to Tanjiro's bed. He rolls his eyes and places the castella on the side as he cleans up the spillage.

"Excuse me" Goto says as he walks over to Tanjiro's bed, "I'm going to set this castella down, so please clear it away after a while. If it seems like it's about to go bad, you can have it".

"Oh, thank you... very much" Tanjiro says as he looks at Goto.

"Hey, he's out of his coma!" Goto yells as he drops the castella on the bed, "make some noise about that! You really are scatter brained, aren't you? You're supposed to call for someone! Say, 'he's regained consciousness!'. You little idiot! Everyone's worried, okay?" he shouts as he goes over to the doorway, "seniority doesn't mean jack, alright? At least, not in this case!" he yells as he takes a deep breath in, "Sakura-sama, Kiyo-chan, Aoi-chan, Sumi-chan, Naho-chan! Tanjiro woke up from his coma!".

The butterfly girls run into the room as they all run to Tanjiro.

"Thank goodness you're okay!" Sumi cries as she holds onto Tanjiro's legs in order to hug him.

"You can have my crackers!" Kiyo says as she holds out some crackers to Tanjiro.

"There's castella on the bed!" Naho says as she looks at the mess on the sheets.

"Gee" Goto says as he looks at the three of them.

There is banging in the hallway as the door slams against the wall, someone with sheets over their head running it.

"Ah, it's a ghost!" the three girls shout as Aoi throws the sheets off of her, gasping for breath.

"Thank goodness you woke up!" Aoi says as she runs to Tanjiro, kneeling down, "since you went in my place! You guys...".

"Thank you" Tanjiro says as he looks at Aoi, "what about the others?".

"As you now know, Sakura-sama is really a demon" Aoi says as she wipes her tears, "she was completely healed from the battle and helped with your injuries. She's been staying here for you to wake up whilst going out on missions. She was just called away to go see Master Ubuyashiki".

"The kid with the yellow hair... was it the day before yesterday?" Goto asks as he folds his arms, "he's back at work! I hear Sakura-sama has sent him out on plenty of missions to help him work on his confidence and such. Against his will, of course. He woke up the day after the battle since he only had minor injuries, so Sakura-sama was able to treat all his injuries. Uzui-san walked out with his wives' help. The Kakushi all recoiled at the sight. Too tough to believe. I mean, they were reeling".

"I see" Tanjiro says as he looks at Goto, "what about Inosuke?".

"Mr Inosuke was also on the brink of death at one point" Kiyo says as she looks at Tanjiro, "Sakura refused to leave his side for days".

"Mr Inosuke was in such terrible shape" Aoi says as she starts to cry again, "because of all the poison in his body, he couldn't stop the bleeding with his breathing in time! Of course Nezuko had burnt it all away by the time he got back here, but it was too late".

"I see" Tanjiro says as he looks up at the ceiling, "so, I must be hallucinating Inosuke stuck on the ceiling above me".

"How are you doing that?" Goto asks in shock as they all look up at Inosuke.

"Good on your for noticing me, Tanpachiro!" Inosuke says as he looks down at Tanjiro.

"Well... I am laid looking up" Tanjiro says as he looks at Inosuke.

"I'm the guy who woke up seven days before you did!" Inosuke says as he lands on Tanjiro's bed.

"I'm so glad" Tanjiro says with a small smile, "Inosuke, you're amazing".

"Keep heaping on the praise" Inosuke says with a chuckle, "and you! You're a weakling! Shame on you for making us all worry!".

"It's you who's not normal, Mr Inosuke" Kiyo says as she gets off of the bed, "Lady Shinobu said as much herself, remember?".

"Oh, wait, Mr Tanjiro!" Sumi says as she shows Tanjiro a page from a book Shinobu gave her, "please take a look at this book! This is a weasel from a foreign country called a honey badger. It had a thick hide like armour. Even getting bitten like a lion can't hurt it".

"It's so cute!" Tanjiro says as he looks at the image in the book.

"Since it's poison proof, it'll just eat up poisonous snakes, too!" Sumi explains happily.

"Wow!" Kanao says as she looks at the image.

"Lady Shinobu said that Mr Inosuke is just like this badger!" Sumi says as she points to Inosuke.

"Lady Kocho makes a lot of irresponsible comments, huh?" Goto says as he looks at Sumi.

"Maybe she just got tired of thinking about him?" Aoi says as she looks at Inosuke, "hey... come on! Get down from there!".

"In other words, I'm immortal!" Inosuke says proudly.

"In your dreams. Are you an idiot?" Goto asks as he looks at Inosuke.

"Who are you calling an idiot?" Inosuke asks as he grabs Goto, "fight me! Step outside with me, scumbag!".

"Hey! Knock it off, will you?" Aoi asks as she grabs Inosuke, "poison doesn't have much effect on you, but neither does medicine, so you need to be careful like Sakura-sama and Lady Shinobu both said! You forget so easily!".

"Be- be quiet!" Kanao says as she looks at them.

"Shut up! Quit yanking at me, you shrimp!" Inosuke shouts as he looks at Aoi.

"What's that?" Aoi asks with a small chuckle, "you're not much taller than me!".

"Tanjiro's asleep, so please be quiet!" Kanao shouts as everyone looks at her.

"Oh man! He went back into a coma!" Inosuke yells as he looks at Tanjiro.

"Would you mind not saying ominous stuff like that?" Aoi asks as she looks at Inosuke, "please just be quiet!".

"Miss Kanao?" Sumi asks as she looks at Kanao, "let's go cook some rice gruel!".

"Okay!" Kanao says with a smile, "let's hope he recovers soon so he can eat tonnes of food!".