As Giyu Tomioka stepped into the Butterfly Estate, he was met by his old crow, who had spent the night perched on the walls. "Giyu Tomioka, I may be old, but my senses are telling me that you should go somewhere else…" it said. Giyu was often put off by his crow, and it was prone to making mistakes, so he thought it would be fine to continue onward.
"Well, if it isn't Tomioka-san." Shinobu said, greeting him as he entered the main building. She looked even angrier with him than she ever had in the past. "The same Tomioka-san who said that a demon reminded him of me? So, why did you come here? Are you here to cut me down like that demon? Are you here to call me hideous like a demon?"
Giyu could now see what his crow had been warning him about. "Koucho-san, please allow me to explain." he said. "Would you be willing to come with me to the forest, with your sword?"
Shinobu's brows furrowed. She could tell that there had been a miscommunication, but his invitation to the forest sounded incredibly suspicious. She was still angry at the contents of the letter, but she felt like he would clear things up while in the forest. "Just to be clear, Tomioka-san." she said, still angry, but not trying to mask it so much. "You do not actually think I am a demon and intend to cut me down, correct?"
Giyu's eyes widened. "Did it actually sound like that's what I meant?" he thought, oblivious to the fact that it somewhat did. "I do not see you as a demon, in the literal sense of the word." he said, playfully jabbing at her temper. However, the playfulness was not obvious, since his face stayed the same the whole time. As a result, it took a little bit more convincing to get Shinobu to accompany him.
When they got to the clearing in the forest, Shinobu suddenly began to feel like he just wanted to duel again. However, her suspicion was corrected soon. Giyu looked at the trees, but not at her. "...It made me uncomfortable, killing that demon." he said, carefully choosing each word. "I could not look at it while it disappeared. It made me feel incredibly uneasy." Shinobu furrowed her brows again. "I don't think I've ever heard him become uneasy, even when facing a demon…" she thought. Giyu continued. "It had the same eyes as you." he said, still avoiding eye contact with her. "To be more clear, the demon reminded me of you. You do not remind me of a demon."
Shinobu was taken aback a little. She was unsure of how to respond, especially at the last comment. Despite getting onto Giyu for being slow to respond, she had to take a moment to consider how she should respond. "Well… thank you, Tomioka-san. Shall I consider this a compliment?"
Giyu continued looking at the trees. "I think that would not be right. I see you as a Demon Slayer; a human. Saying that you do not you do not remind me of a demon is an objective fact. It is not a compliment." he said calmly. Shinobu clenched her fists, hurt by his words. She was about to say something before he cut her off. He looked down from the trees and over to her. "However, you are… better… than just a human. That was a compliment."
Shinobu's fists were still clenched, but it was no longer out of anger. She was doing her best not to burst out laughing. "That's his idea of a compliment?" she thought. However, despite her attitude towards it, her heart felt lighter after he spoke his mind and complimented her. She stifled her laugh for a little bit more, but Giyu did not catch (or seem to care) that she was laughing; he had gone back to staring at the trees. Shinobu wiped her eyes, which had teared up from laughter. "Did you have me come to the forest just to say that?" she asked happily.
Giyu thought about it for a moment and decided to speak his mind again. "I'm in your debt." he said, not really answering her question.
"Tomioka-san, that has nothing to do with what I just asked." Shinobu said. She had a smile on her face, but her voice sounded exasperated from dealing with his behavior.
"It does." Giyu replied. "I brought you here to repay my debt to you; for all of the time you took helping me recover, helping me become… likeable. The demon I fought gave me an idea, one that I would like to share with you. I want to help you develop a fifth breathing form for the Breath of Insect."
Shinobu's eyes widened. "Tomioka-san, that seems awfully unlikely to happen, since you can't use any of its breathing forms." she put bluntly.
"I know. I cannot use it myself, but I would like to at least give you the idea." Giyu said, then he looked over to her. "The Breath of Insect is a descendant of the Breath of Water. I feel like it's possible that I can at least communicate my idea. And you, Koucho-san, are the only person who could possibly make the idea a reality."
"Imagine a praying mantis lying in wait, for some unfortunate creature to get within its range." Giyu said, conveying his thoughts to her. He thought it could be a series of powerful double-thrusts that would immobilize or kill demons. Because of the incredible speed of the praying mantis, which this move was to be based on, it would be possible to execute without gaining any momentum. Essentially, this move would be the perfect blend of Giyu's ability to adapt to situations and Shinobu's ability to thrust her sword multiple times in a second. Giyu and Shinobu toiled in the forest for hours, training to be able to achieve such a feat. The closest existing breathing form to this theoretical move was Breath of Water, 11th form: Dead Calm. Because of this detail, Giyu trained Shinobu how he trained himself.
After only a few hours, Shinobu had trained her body to be able to thrust four times in a second without any buildup, momentum, or movement from her feet. It was likely not yet enough to be a breathing form on its own, but her body now had the foundation to improve and turn it into a breathing form in the future. Even until then, she would be able to slaughter an attacking demon in less than a second.
Shinobu huffed, catching her breath after the intense training. She looked up at Giyu, who was sweating as well, but was not breathing harder than normal. She was irked that she had been the only one working hard, but she was also fairly glad that he trained her. He agreed that she had made enough progress to stop training for today. "Koucho-san, I'm very impressed." he said as they were walking back to the Butterfly Estate. "...That, too, was a compliment." Shinobu just giggled in reply.When they got back in, the girls were giving Tomioka stares. "Koucho-sama…" Aoi said, whispering into Shinobu's ear. "Should we escort Tomioka-sama out?" Shinobu stared at Aoi, confused. Apparently, from the conversation the two pillars had while they were indoors, the girls were under the assumption that Giyu only came here to insult Shinobu and duel her.
"Actually, just escort Tomioka-san to the male's baths. He looks- and smells- like he could use one." Shinobu said while laughing. Giyu heard what she said, but he chose to ignore it. He didn't bother waiting until the girls stopped laughing and began to escort him; he just walked to the bath on his own. He soaked for a few minutes in complete silence. Suddenly, Giyu heard something from over the wall. "Yoohoo, Tomioka-san." he heard Shinobu say. "Thank you for helping me. I actually feel like you've done something nice for once."
Giyu was not sure whether he should respond. He did not feel comfortable talking while he was in the bath, especially if he was talking to a female. However, he had become more conscious of people's feelings, and he knew that if he just tried to ignore her, she would be annoyed or hurt. "...You should not thank me. That was my way to thank you." he said plainly.
"Ah, but you see, Tomioka-san. It is my duty to help people recover from illness and injury, so there is no need to thank me for that." Shinobu said, a cheeky grin forming on her face. "So, I suppose you're thanking me for teaching you how to become more likeable? Well, in that case, I accept your thanks. However, I should be the grateful once, since you are so much more bearable this way."
"It has helped me a lot." he said with just the slightest hint of happiness in his voice. "At first, speaking with strangers was still challenging. But if I imagined you were there, I would be steered in the right direction, and could talk. Eventually, it felt like a second nature; though, I'm sure it's below your standards."
Shinobu laughed. "I'm thoroughly impressed, Tomioka-san. I was worried that you wouldn't survive a conversation with a stranger without me there, but it looks like you've actually grown." she said both cheekily and genuinely.
Giyu sat in silence for a moment, deep in thought. "...What exactly made you decide to teach me how to become more likeable?" he asked. Both of their backs were against the wall, making one less than a foot apart from the other. "You seemed to rather enjoy disliking me, yet you gave that up."
Shinobu laughed. "Believe me, you don't know that I've given that up." she said, as cheeky as ever. "But to answer you… I did not want you to dislike yourself. I felt like trying to talk to you and get you to talk with others would make you happy- or at the very least, you would seem less unhappy."
Giyu did not respond. He was thinking about his past, and how he would probably never like himself. "Tomioka-san?" Shinobu chimed, worried about the oppressive silence. "To tell the truth, I do not dislike you. In fact, I never have."
Giyu stood up from the water and put a towel around his waist. "...Thank you, Koucho-san. I wish I could say the same of myself." he said as he went to get his towel. Shinobu stayed quiet, sad about the last thing Giyu said. Before exiting the bath, Giyu stopped. "Oh, and Koucho-san… I don't dislike you either." he said, leaving an air of finality. Even though he was sad about remembering his past, he was happy to hear Shinobu's words.
Shinobu sunk in her bath a little and began to blow bubbles. "Did I actually get through to him?..." she thought, feeling heat rise to her face. She sighed and sat back up. "I doubt it…" She got out of the bath and dressed back up. Her girls noticed that she seemed a little downcast while eating dinner. However, when she was inquired about the reason to this, she brushed it off as nothing.At that, Giyu left from the Butterfly Estate and went home. His house was the most modest out of all of the pillars, and he had nobody there with him, so there was nothing to do exactly. He supposed he could read through all of the letters he's ignored since his injuries, but he did not suspect that he would be responding to many of them.
Giyu Tomioka
I heard that you have been injured. The Insect Pillar informed me of some of the abilities the demon had. I find it frightening that such demons can exist and not even be a Moon. However, I am glad that you are in recovery. Please, take care.
-Sakonji Urokodaki
Giyu decided that he would write his old teacher back. He saw Urokodaki as somewhat of a father figure, and he knew that he would very badly regret hurting him or making him worry.
Tomioka-san
I'm so sorry you got injured! The way Shinobu-chan described it made it sound really painful, I'm so sorry! I asked if I could send any sweets, but apparently you had to stick to a certain eating schedule for your rehabilitation… If you get this while you're at the Butterfly Estate, tell Shinobu-chan I said hi! Oh, and you should really try flirting back at her! The way she talks about you is so sweet!
Anyways, take care!
-Mitsuri Kanroji
Giyu stared at the paper in front of him. "Flirting back?" he thought. "Was she ever flirting with me to begin with?" He somewhat doubted the truth to this, but if the Love Pillar seemed to think this was the case, then maybe he needed to be more observant and reevaluate this later. Either way, he didn't even know how to flirt, especially with someone as frightening as Koucho, so he didn't imagine that he would actually follow Kanroji's advice. He thought for a moment. "She didn't have to write to me… I should show some gratitude." he thought, accepting that he would be writing to a pillar other than Koucho for the first time.
To Giyu Tomioka
I saw your injuries before I left from the Butterfly Estate, but I wasn't able to ask how long you would be out of commission. I really hope you're alright. I've personally healed from my injuries. Did you hear about what happened on the Infinity Train? I defeated a Lower Moon! I'm certain that Oyakata-sama already knows this, but I'm just so happy about it! Now the other pillars might start accepting Nezuko!
I wish you a speedy recovery!
-Tanjiro Kamado
Giyu set the letter aside for now. He owed Tanjiro a thanks for inadvertently inspiring Giyu's method for slaying the mantis demon, but he was irked at him for the moment. He was mad because Tanjiro had strayed from the Breath of Water.
A few days before Giyu Tomioka battled the flute demon…
Kyojuro Rengoku boarded a train, which had a roundabout route, only stopping at stations. He boarded it due to reports of missing people; there was a demon on the train. On the train, he meets Tanjro Kamado, Zenitsu Agatsuma, and Inosuke Hashibira. Without knowing it, Tanjiro had saved Kyojuro's life.
The demon tried to hide itself on the train, but Tanjiro was able to find it and battle it, despite setbacks of being put to sleep. After everyone woke up, Kyojuro dashed all over the train, slaying demons and saving passengers. As he dashed to the front car, where Tanjro was, he inadvertently became a wielder of an incredible power. Tanjiro, who was battling with all of his heart, had grown a mark, which he was never aware of, on his forehead.
After Tanjro destroyed the demon, the train was derailed. Suddenly, another, far more fearsome demon bared its fangs, assaulting the demon slayers. Kyojuro Rengoku was the only one who stood a chance against this demon. Under normal circumstances, Kyojuro would not have slain the demon, or even survived until sunrise. However, after coming in contact with Tanjro during battle…
Kyojuro wanted to protect everyone. He thought of the demon slayers behind him, who defeated the most powerful of the Lower Moons. He thought of the innocent bystanders who would be torn to shreds by this fiend. He thought of his little brother, who was at home, waiting for him to return safely… Kyojuro's eyes opened wider than normal. His heart began to beat out of his chest, and he felt an enormous second wind coming. Tanjiro already couldn't comprehend anything that was happening, since Kyojuro and the demon were far too fast. However, Tanjro could comprehend this: Kyojuro had an entirely new air about him. He seemed to have this demon on the ropes, assaulting it from multiple directions in a single second.
Tanjiro ended up passing out from exhaustion. When he woke up, it was morning, and he was being carried by a Kakushi. He looked around, but he was unable to gather much information from his surroundings. When he arrived at the Butterfly Estate, he was able to regroup with Nezuko, Zenitsu, and Inosuke, given the fact that they were all in the infirmary with him. Nezuko was sleeping in her box while Zenitsu and Inosuke were awake in their beds. Tanjiro feared for the worst. "Rengoku-san…" he thought, a lump forming in his throat.
Just then, someone walked into the infirmary. "Yoohoo, Tanjiro-kun." Shinobu Koucho said, noticing her esteemed guests and patients. Another person followed right behind her, and Tanjiro's eyes watered up.
"Hello, Kamado!" the jovial, enthusiastic, and loud voice of Kyojuro Rengoku said, filling the room with excitement and joy. He looked over the three. "I'm very impressed with all of your performances today! Come be my tsuguko! When you're healed, that is!" All three of the teenage Demon Slayers cried from joy. Kyojuro Rengoku, having received the mark, not only survived his encounter with the Upper Moon 3rd, Akaza, but he also managed to slay the demon.
So, although Zenitsu in particular would not be learning the Breath of Flame, all three of the boys would go to train under Kyojuro Rengoku as his tsuguko.