(A/N: One year has passed since the last chapter, so you and Mitsuri are 6 years old now. In that time, Mitsuri has been acting very cold towards you. Despite that, Mitsuri has't stopped sleeping in your bed in that time. Everyday, you ask her if she could stay home for one day instead of training everyday, but she always responds in a cold manner. Your father has not done anything besides getting mad at your mother and sometimes Mitsuri yet.)
Mitsuri woke up before Y/N and the moment she saw her twin brother sleeping peacefully with his arms wrapped protectively around her waist, she started blushing hard because it looked like a lovers embrace to her. She thought about that sometimes after training, love and things like that. She never was able to say that she felt love to anyone except Y/N, but always came to the conclusion that it was simple sisterly love. But after what he said one year ago, about protecting her and stopping her father from becoming worse, she saw him in a different light. Even though she hated it when he wants her to stay home, she was pretty sure this was more than sisterly love, but she did not dare tell anyone because she knew that she should not feel like this towards her brother. Just as she started panicking about how she should deal with these feelings, Y/N started to stir awake, looking at his sister in the process.
Y/N: "Good morning, Nee-chan. Did you sleep well? I hope I did not squeeze you too hard, I tend to do that sometimes."
Mitsuri: "N-no you didn't, Nii-chan, I-I actually quite liked it."
Mitsuri was freaking out why she was stuttering like that all of a sudden. Was it because of her feelings for Y/N?
Y/N: "Oh, right I forgot, don't you have to go train with Rengoku-sama today again?"
Mitsuri: "Yes I do, why?"
Y/N: "I was wondering if you could sta y here with me for tod-"
Mitsuri: "No, for the last time, I will continue training and become a demon slayer. I'm not going to stop just because you are sick."
Y/N: "B-but-"
Mitsuri: "No buts. Now, stay in bed until i come back, alright?"
Y/N: "H-hai, Onee-chan."
As Mitsuri was getting ready for training, Y/N was wondering what happened. Ever since he got sick, his sister has been acting more and more cold towards him, but he still loves her with all of his heart. He also started thinking about how he would stop his father from becoming the worst he could get. With his sickness, it became increasingly harder for him to try stop him, but he was still determined to keep his sister and mother safe, and if he will have to murder his father for it, then so be it. He did not care about his father, nor did he know why that man saved him when he got sick, most certainly because his mother would be incredibly sad. Just as his thoughts became more violent, Mitsuri came back in his room with her training clothes on and her nichirin katana strapped to her hip.
Mitsuri: "I'm going now, Onii-chan. Please don't overexert yourself while i'm gone, alright?"
Y/N: "I won't, but I think I will visit the new person later."
Mitsuri: "New person?"
Y/N: "Yes, a new family has moved into town today, Didn't you hear? I heard it's just a mother with her daughter, she is about our age if I remember correctly."
Mitsuri: "Hm, I didn't know that. Then I can maybe visit them after training."
Y/N: "Yes, maybe you can do that."
Mitsuri the left while waving to Y/N who was looking out the window sad. After she left, Y/N then got out of bed, washed himself and dressed in his clothes for the day (You choose.). He then grabbed the cane he recieved from the blacksmith, he found the silver snake ornament resting on the handle quite nice. He got it to help him walk since it was quite hard to do so with weak bones.
He then stepped out of the now empty house. Oh right, forgot to tell you, F/N went on a mission 4 months ago as a demon slayer again because its an emergency and he was requested to come back to the HQ for a mission. From what Y/N heard, the mission involves an uppermoon, number three to be exact. Y/N knew about this demons infatuation with turning slayers with a high fighting spirit into demons. Y/N was aware of the high fighting spirit of his father and he knew that even though he retired, he was always craving for more power. Considering the fact that his father will cross paths with uppermoon three, the boy already knew what his fathers decision will be, and he will stop him if he comes back, whatever the cost may be. M/N is shopping at the market, but both of the children noticed her coughing heavily from time to time and needing help a lot more than usual. Mitsuri didn't think anything of it, but Y/N noticed that it was something that was not just a passing cold. He thought about this for quite a while and didn't notice he already arrived at the house of the new family, and noticed the mother with her daughter unpacking and bringing stuff into their new home. As Y/N walked up to them, the woman noticed the boy approaching them and greeted him cheerfully.
???: "Hello cutie, may I ask who you are? Do you live here perhaps?"
Y/N: "Yes, I do. My name is Y/N Kanroji, I live in the big estate in the middle of town. It's nice to meet you...?"
???: "Oh, right, sorry. My name is Anaka Taomi, and this is my daughter Mukago, come on say hello to the boy sweetie."
Then the girl came forth from behind the womans legs. She was pretty young and small, most certainly in the same age as the twins. She had short black hair with some bangs falling in between her eyes. She was wearing a red kimono with a black obi strap. She also had dark grey eyes that radiated kindness and, to be honest, Y/N thought they were beautiful. She looked to be pretty shy so he approached her first to help her ease into the conversation.
Y/N: "Hello, my name is Y/N Kanroji, I am 6 years old. It is nice to meet you, Mukago-chan."
Mukago: "H-hello, I am Mukago Taomi, I am 6 years old as well. Umm, why do you need a stick to walk?"
Anaka: "Mukago, that's rude!"
Y/N: "No, it's alright miss, I don't mind. You see Mukago, I need this cane because is have a rare disease that is constantly weakening my body and bones. At first, i was able to walk normally, but since a few months ago, I randomly start to fall down while walking, so the blacksmith made me this cane."
Mukago: "Oh, ok then. Does it hurt when you walk?"
Y/N: "No, my body simply does not have the strengh."
Mukago: "Ok, I get it. Do you want to be friends maybe?"
That sentence surprised Y/N. Ever since his sickness started taking effect, he never had any freinds, just his sister. Because of this, his thoughts started racing in a million different directions. Is she saying the truth? Does she really want to be his friend? Does she just want to use him? He couldn't tell, but then he looked into her eyes again, those beautiful grey eyes. He didn't know how, but they just made him trust her instantly.
Y/N: "Yes, why not. Let us be friends then."
He then hugged her which made Mukago blush very much and her mother just started laughing at the two of them. Just as Y/N stopped hugging a red Mukago, Mitsuri started running towards him with a scared look and her katana in hand.
Mitsuri: "Onii-chan! You need to hide! There is a demon in the village, and he can stand in the sun! Quick, come with me, you can hide with the other villagers."
Y/N: "And what about you?"
Mitsuri: "I'm gonna look for Okaa-san, she is the only one I haven't found yet."
Y/N: "I don't think so."
Mitsuri: "Wha-"
In a flash, Y/N has passed Mitsuri with her katana in his hand and his cane in the other. Mitsuri couldn't understand how he did that despite his sickness.
Mitsuri: "Onii-chan, what are you doing?"
Y/N: "I will need to do this myself. You bring Mukago and her mother to the other villagers and then hide with them. I will join you later."
Mitsuri: "But Onii-chan, you-"
Y/N: "No, I won't accept any kind of rebuttal from you. This is my task, I made a promise, and I will fulfill it."
Mitsuri: "I-...bu-...ok Onii-chan, please be safe."
Y/N: "I will, trust me"
Y/N: 'Maybe she won't be so cold anymore if I win this battle...
...maybe.