Disclaimer: I do not own Demon Slayer or any of its characters. All rights to the former and latter belong to Koyoharu Gotouge.

The Butterfly Estate was like a second home to Giyu Tomioka. Although he would scarcely suffer any real injuries during his missions as a Demon Slayer, he was required to undergo check-ups often. For context, Giyu Tomioka is a Demon Slayer, specifically a Pillar of it. The Demon Slayer Corps is a group of people who hunt super powerful, nocturnal, and flesh-eating demons. The Pillars of the Corps are the amazing, powerful- but most importantly- unshakeable, top members.

Out of all of the Pillars of the Demon Slayers, none could be argued to be more or less shakeable than Giyu Tomioka. Giyu Tomioka was the first of the Demon Slayers to actively avoid killing a demon that he easily could have slain, even though it was a special case. He did so twice- both for the same demon. He not only broke the rules of the organization by letting a demon survive, but he did so by restraining a fellow pillar who was attempting to kill the demon.

It could also easily be argued that Tomioka was unshakeable. None of the other Demon Slayers were so straight laced, seeming to care about nothing more than slaying demons. Even though he has been a pillar for years, he does not fraternize with any of them, and would call none of them anything more than comrades. Despite the efforts of some to see a face other than a stoic one take the place of Tomioka's, none have succeeded.

Despite what his face shows and words tell, Tomioka is actually quite capable of feeling things. He would often feel most things while he is at the Butterfly Estate. This time, he was being evaluated for any broken bones after he slayed a demon that had terrorized a village. Of course, he suffered less than even a scratch, but he would not be cleared to take another mission unless he passed the check-up (unless an emergency called for a Pillar to immediately take action).

Tomioka felt like it was a hassle to come here, but he walked inside nonetheless. As soon as he opened the sliding door, he saw the face of the medical specialist, Insect Pillar, who seemed to be seething with rage, despite the smile on her face. "Tomioka-san… are you so stupid that you enter a lady's room without knocking, especially at night time? How hateable can one man be?"

Tomioka stared at her with his blank, statue-like face. "Is it that wrong?" he thought, his face remaining unchanged. "...I need a checkup…" he said calmly.

Veins were popping out of the lady's forehead. "Is that so?... Then I suspect I'll find that you've been killed by poisoning, during this checkup. How unfortunate…" she said as she took a menacing step towards him. When Tomioka did not move, her veins protruded even more. "Get out of my room, Tomioka-san." Even as she said this cruel-sounding thing, her words sounded as if she was singing.

"Oh, so that's what she wanted…" he thought as he turned around. "...Koucho, please hurry." he said as he exited through the sliding door.

"No, I won't. Aoi-chan will check up on you, if you don't scare her away with your hideous face. Good night, Tomioka-san." Koucho said angrily, slamming the sliding door shut behind Tomioka.

"There are so many fireflies tonight…" Tomioka thought as he made his way to the main building of the Estate. Once again, he entered unannounced, but it was more acceptable this time. He walked to the infirmary, where the aforementioned Aoi would most likely be. He was correct in this assumption; she was there, checking up on three familiar faces. "This is a hassle…" he thought as a familiar voice exclaimed, "Tomioka-san!" Tomioka stared at the source of the voice, not saying anything in response. It was Tanjiro Kamado, a friendly (annoyingly so, to Giyu), new Demon Slayer. The only reason Tanjiro even knew Tomioka was because Tanjiro's sister, Nezuko was the demon that he decided to spare, causing little other than external strife for him.

Giyu looked from Tanjiro to Aoi. "Please wait one minute, Tomioka-san." Aoi said. Tomioka's eyes widened ever so slightly, and Tanjiro voiced his concerns. In the Butterfly Estate (and all the Pillars' estates), it was customary for the assistants of pillars to refer to all of the pillars respectfully. By referring to Giyu as "Tomioka-san," instead of "Tomioka-sama," Aoi was being disrespectful. After hearing Tanjiro's concerns, Aoi looked from Tanjiro to Giyu. "My apologies, but Koucho-sama has asked all of us at the Butterfly Estate to refrain from adding 'sama' to Tomioka's name."

Tomioka did not say anything or react in any way. "I should have suspected…" he thought as he simply walked to a nearby bed to sit in, waiting for his turn to be checked on. Giyu Tomioka and Shinobu Koucho seemed to always be at each other's throats- or- Shinobu Koucho seemed to always be at Giyu Tomioka's throat. He thought that her hatred towards him could hinder them down the line, since the two often had to work together. He remembered how, on their mission to Natagumo Mountain, she tried to murder him with a blade concealed in her sandal. He, in his infinite wisdom, realized that this could cause problems down the line. So, he pondered the possible reasons that she hated him so much.

He could not find a reasonable answer. At first, he considered that she found him to be too unresponsive to things, but even when he would respond or show emotion, she seemed disgusted and annoyed. He then considered that it could be because he let a demon free, but he figured that couldn't be the case since she was having her subordinate take care of the demon. Suddenly, an answer appeared in his head. "Perhaps I really am unlikeable…" he thought, his heart tightening a little. He did not care too much, but it hurt him to realize that the people he thought he was civil with were probably all disgusted by him, perhaps even more than Koucho since none of the others went out of their way to converse with him. Tanjiro saw Tomioka's face grow a percentage more sullen. "Everything will be okay, Tomioka-san…" he thought as he tightened his fists.

After Aoi finished checking up on Tomioka, he bid everyone farewell. He walked to Koucho's room, where he entered without permission once more. "Tomioka-san, if I turn around and see your face, I'm going to run you through with my blade." she said in a sing-song voice.

"...Sorry, Koucho…" Tomioka said. "Yeah, that just confirms it…" he thought as he left and slid the door shut behind him. He didn't realize that Koucho's aggression stemmed from him breaking into her room twice in one night; instead, he just assumed that his hypothesis was right, and that he was doomed to be the least liked among the pillars.

After the door was shut, Shinobu Koucho's eyes widened a little. "Did he just… apologize?" she thought as she went to look out the door. Upon opening the door, she found that Tomioka was already gone. She shut her door once more, feeling both relief and regret. "Perhaps he's a human after all…"

At the next Pillar meeting, Shinobu tried to make conversation with Tomioka as she normally would. Generally, while Oyakata-sama, the head of the Demon Slayers, was not present, Koucho would prod Tomioka and try to get a reaction out of him for her amusement. However, Tomioka was tuning her out, even more than usual. Since it was ordinary for Tomioka to not respond to her, she poked him to get his attention. The poking did not phase him either, at least outwardly. On the inside, he was beginning to boil with annoyance.

Once Oyakata-sama showed up, the pillar meeting started, and Koucho stopped poking Tomioka. After the pillar meeting ended, everyone took some time to socialize. Everyone except for Tomioka. Even though he just received orders to depart for a mission alongside Koucho, tomorrow morning (they were often paired together for missions), he prepared to leave immediately. He had not spoken the whole time except for when Oyakata-sama was present, and questions were directed at him.

"Tomioka-saaaan…" Koucho said, following him as he was trying to leave for his house. "Let's get along on this mission, Tomioka-san."

At this, Giyu paused and stood in place. "...I believe you know that isn't possible…" he said, and dashed out of sight immediately after. Koucho stared at the place he was standing. "Perhaps I've gone too far…" she thought, confused for a moment. Right after, though, she shook her head. Her fists clenched tightly and her blood boiled. "He's the one who's impossible to deal with! I shouldn't feel bad for him!" Seeing this interaction, Kanroji, the Love Pillar, shook her head and sighed.

The next morning, at dawn, Giyu and Shinobu met at the Oyakata Estate to depart for their mission. No words were exchanged, only spoken. Shinobu, while they were both running, kept saying, "Let's get along, even though you say it's impossible," and "If you keep ignoring me, things will only get worse." Of course, Giyu didn't respond at all. Shinobu's veins were popping out of her forehead, not that Giyu noticed.

About halfway to their destination, Giyu spoke up. "...I've found a new doctor." Clearly, everything he was thinking did not match up with everything he was saying. To him, he was stating that he no longer had to burden Shinobu with his routine checkups and presence. It made him a little sad to say goodbye to Butterfly Estate, but he would find a new "second home" at the residence of this doctor close to his home. To Shinobu, however, he was simply trying to sever his ties with her, being petty because he may actually be offended.

"Why do you keep saying things like this? You truly intend on being unreasonable forever? This is why nobody likes you, Tomioka-san." she replied, anger shaking her voice, yet with a smile plastered on her face.

"...I'm sorry." he said, and he said nothing else the rest of the trip. Once they arrived at the forest, they split up and searched for the target demons. Supposedly, many demons had congregated to this forest, eating the human residents and scaring away the local fauna. There was also rumor of an especially powerful demon that had ambushed and taken out a group of eleven slayers.

"It's probably a lower moon, then." Koucho thought to herself while darting off to the east. She very quickly realized that most of the demons in the forest must have congregated here. This was no real issue for her though. As hordes of demons did their best to overwhelm her, she lanced through their necks like a shish-kebab, severing their heads from their bodies with a wisteria poison. Additionally, if she were to legitimately become overwhelmed, she would have no trouble evading the relatively weak demons. After the hordes stopped, she assumed that she had killed all of the demons on her half of the forest (she slayed 24 demons). She turned around. "I bet Tomioka is dealing with the powerful one…" she thought as she made her way over to where he was.

Koucho heard a loud crash coming from Tomioka's direction, followed by a tremor. "A tree fell?" she thought. A piercing wail filled the air, making her pick up the pace.

While Shinobu made her way to the east side to fight demons, Giyu was investigating the west side. He carefully analyzed the surroundings, knowing that the demon would try to ambush him. Giyu realized that he could not hear anything in this general area. However, he felt the vibrations of leaves rustling behind him, so he slashed the air behind him, perfectly parrying an attack. Giyu lowered his sword and prepared for another attack.

The demon standing in front of him was human-sized, with white skin and hair. It had a pattern of a red ripple originating from its chest, reaching down to its arms and legs, and hanging around its neck was a flute. Its eyes did not have any number seared into it, but Giyu gained the impression that this was not a normal demon. Giyu waited for it to make the first move, but it seemed to wait as well. "What's wrong, human? Not going to strike, or even make any small-talk?" the demon said, taunting him. Giyu knew that rising to his provocations was probably a mistake, but he also knew that he shouldn't give the demon the chance to plan anything. "Fine, then." The demon said, raising the flute he had to his lips. Giyu lunged at him with blinding speed, aiming for the neck, but as soon as the demon blew into his flute, he disappeared. Giyu was put off. For some reason, he could only hear his own thoughts, his own voice, the demon's voice, and the flute's notes.

Giyu felt an intense bloodlust coming from his right side and slashed at the right time, again parrying the demon. "Tch. You're good, human. I bet you'll taste good too." he said, then blew into the flute once more, disappearing. Giyu checked his surroundings, but he didn't notice anything other than another feeling of bloodlust. After being parried a third time and slashed at once more, the demon bared its fangs. "Fine, then I'll just have to show you what I've got." The demon was far away from Giyu, so he figured he would have to brace for a projectile.

"Breath of Water, 11th Form. Dead calm." Giyu said, recognizing the threat that was coming.

"Blood Demon Art! Reverberation!" the demon cried out before blowing a shrill note, and he disappeared from sight. Giyu sensed multiple clones of the demon approaching from any side of him, but few of them got too close. However, the ones that did were immediately decapitated. Suddenly, Giyu felt a sharp pain in his wrist. "Impossible…" he thought as he checked the source with his peripheral vision. The 11th form of water breathing was incredibly useful for any sort of attack that came from the area surrounding the user- as in, where the demons were. However, this blood demon art seemed to have spawned a demon on Giyu. A pure white arm was protruding from Giyu's stomach, taking hold of his left wrist, squeezing it until there was a sharp snap.

"Hehehe! What do you think of my music?" the arm of the demon, which had grown eyes and a mouth, asked. Giyu immediately severed the demon from his body. His calm was now broken, but he could manage. He would manage. He observed his surroundings. There were three of the clone demons. Giyu could tell that these were clones since they didn't have any flutes around their necks. He tightened his grip with his right hand. A demon clone rushed at him, and he slashed through it, decapitating it immediately. However, as soon as he did that, the other two lunged at him from behind. He was able to decapitate one, but the other landed a blow on his right shoulder before dodging.

"Well, it looks like you're just another one to succumb to my music…" the demon said. "And it's such a pity, too. Nobody's fought quite like you, not even a horde of swordsmen could be your equal." The demon raised its flute to its mouth once more. Suddenly, Giyu thought of something. "Reverberations… music…" he thought, connecting some dots in his head. He would have to test his hypothesis and maybe die, or lose his right hand and definitely die.

"Breath of Water, 6th Form: Whirlpool." he said, holding his sword as tightly as he could in his right hand. "This is a two handed form, but I'll have to sacrifice a little accuracy and hold on extra tight…" he thought as he created a hard-to-control torrent of water around himself. Just as he did this, the demon cried out its blood demon art once more, and it once more blew into its flute. "I was right." Giyu thought as he saw a skinny, weak-looking version of the demon appear in the torrent just to fall into shreds. Giyu realized that the demon used its flute with its art. Wherever the sound from its flute could bounce off of, the demon could make clones appear. So, to solve this, Giyu surrounded himself with already-loud water to make the sound not reach him. However, as he could not control it very well with one arm, he stumbled, and his sword halved a clone as well as the tree that the music that spawned it echoed off of.

"Tch. That was unexpected…" the demon said. "But that's not all of the secrets I've got in store…" His pointed teeth were bared in a wide grin. Giyu, who heard no noises right now, made sure to check his surroundings. There were two clones (one and the one that he cut in half) and the original demon remaining. The clones seemed to be staying at bay. Suddenly, the demon blew into his flute, but it did not play a note; the noise that came from the flute was akin to the screams of many humans, all laid atop one another. The sound was loud, but not deafening, so Giyu didn't cover his ears. However, he soon realized that this was a mistake. He stumbled, having to support himself on the tree that he sliced.

He quickly regained his balance and sliced a clone that had appeared on his left. "I have to finish this quickly." he thought as he darted at the flute demon. The demon blew into its flute once more, and it disappeared. Suddenly, it dashed at him at blinding speed, seeming to bounce off of a nearby tree as fast as his music did. Giyu was barely able to react, and only managed to cut its throat, not going all the way through. "Guh!" the demon said, astonished at Giyu's reaction speed. Suddenly, the clones appeared. The one that was cut at the waist snuck up, taking advantage of its lowness on the ground and the lack of noise in this area, and grabbed onto Giyu's heel, pressing its thumb into it and leaving a hole. Giyu quickly decapitated it, as well as the whole one which was less subtle about sneaking up on him.

"Hehehe, it looks like you're out of op-" the demon was cut off from finishing its taunt. A powerful, lightning-fast thrust of a katana pinned it to a tree via the throat. "Guhh…" it said as its face contorted into a look of hatred. It had a smile, as if it was victorious. After all, simply stabbing its throat wouldn't kill it, right? Suddenly, its neck started melting, severing its head from its torso.

"Goodness, Tomioka-san. I believe this is the first time that the Kakushis will have had to take you." the taunting voice of Koucho rang out to him. "That's just pathetic. I mean, this demon was no moon."

Giyu stared at the ground. "...Thank you, Koucho…" he said as he began to try and limp away from the scene of the battle. He immediately stopped moving, and his face almost contorted as tears poured down his face. "That hurt… a lot…" he thought as he sat down, deciding it was for the best that he just wait for the Kakushis. His body had become painfully aware of the gaping hole in his heel.

He looked up and saw the face of Shinobu, looking down at him in worry. "Why does she seem concerned?…" he thought, very confused now.

"Tomioka-san, what's wrong with you?" she asked angrily, yet with a smile.

Tomioka thought she was asking why he was crying, and reasonably so. "...My heel was torn." he said in response, tears still pouring down his stoic face.

Her smile did not fade, but veins popped out on her forehead, indicating that she would be losing her temper soon. "Not that, Tomioka-san. I know that. I also know why you had such a difficult time against that foe, and do not think less of you due to it. What I don't know, or can't understand, is why you've been acting like you hate being a pillar. Now that you can't easily escape me, please, let me indulge in hearing your reasoning."

Tomioka remained unmoving and pondered the question. "...You are right, Koucho." To him, that was a sufficient response. Again, the words in his head were not the same as the words that left his mouth.

Shinobu looked like she was about to strangle him. "This does not help me at all. Saying, 'You are right,' is not a reason."

"...I am not liked. I should not have doubted you when you said it before…" he said simply. "...I don't want to burden anyone unnecessarily with my presence…"

Shinobu's eyes widened a little. "He really lingered on that?..." she thought as she sat down across from him. "Hmm… well, it might be true that you are not liked by some. However, what I said was an exaggeration. I know you are too simple to understand banter, but please know that not everyone actually dislikes you." she said, not exactly trying to hurt his feelings nor spare them.

Giyu continued staring. "...I am sorry for not understanding anything." he said, also simply. "...And I am sorry for everything I've done because of that."

Memories of a night not too long ago, when he entered her room unannounced, twice in one night, flooded into Shinobu's mind. Her veins looked like they were about to pop. However, she did not lash out. "He's actually saying he's sorry for all of this." she thought, calming herself down. He thought for a moment, and slowly she switched from a fake smile to a real smile. "Well then, Tomioka-san." she started, clapping her hands together. "I suppose that while you are healing, I will teach you everything you don't understand."