You people asking for a sequel inspired me to write one LOL

This is more about how Kamui reacts to Okita with his sister.

Upon the entrance of their apartment unit, Kamui notices another pair of sneakers neatly placed on the shoe rack. His eyebrows almost met upon realizing that it was a man's (they were too big for a girl and it didn't really look feminine). Kagura was definitely home, her pink slippers were replaced by her school shoes, and it was starting to bother him as to who the visitor was.

"Kagura-chan!" he called out as he ascended the stairs.

The unit wasn't that big. It had two rooms, a living room, a kitchen, and a bathroom. Upon the end of the staircase would be Kagura's room and next to it was Kamui's. The living room was just outside his room and the kitchen was next to it. Lastly, the bathroom was located on the right side of the staircase's end, parallel to his sister's room. It wasn't big so Kagura was definitely supposed to hear her brother's voice.

Kamui called out once more only to be surprised that a sandy-haired lad came out of his sister's room.

"Ah, Mr. Pervert, you're here today." He scratched his head. Was there an upcoming test that he forgot about? Surely there was because Kamui couldn't think of another reason why Okita would be here again. "I don't think we have any upcoming tests, why are you here?"

Okita trotted through the living room and headed for the kitchen. "Tsk. I liked it better when I was still 'Mr. Policeman'." He said, not answering Kamui's question. Kamui didn't really mind that Okita was feeling more than "at home" in his apartment. Hell, he always acted like that around Abuto's place, so he wouldn't be really practicing what he would preach.

The redhead headed for the couch and turned on his TV to watch the news. Being a business major didn't excuse him from keeping up with current affairs about the law. It also didn't excuse him from cleaning up the piles of newspapers and cups of instant noodles, but he didn't, anyway. He couldn't focus on the news because the clanking of pots in the nearby kitchen was becoming unbearable.

"I wouldn't even try, if I were you." He called out from the couch. "You won't be able to find anything to cook in that kitchen."

Okita clicked his tongue. "Alright, it seems I'll be buying your sister dinner again." He came out of the kitchen and took his jacket that was draped over a chair. "I'll be back."

Kamui hadn't registered that Okita was once again paying for Kagura's dinner but only understood that his sister was hungry. His hand searched under the coffee table to find an unopened cup of instant noodles. He quickly went into the kitchen to prepare it and headed for his sister's room.

"Kagura-chan! Here's dinner." He outstretched his left arm while he leaned on her doorframe. He offered it to her again only to be vigorously rejected.

"You can have that, Aniki. The Sadist is buying me dinner." Kagura said from her desk. Kamui thought that it was odd that Okita was buying her dinner. Come to think of it, the reason why the kitchen was empty for the past few weeks was because Kagura kept on eating outside. And if she was eating at home, it was the Sadist who bought her meals.

"Are you sure?" He smiled. "More for me then!"

X

"Oi, Mr. Pervert," Kamui said, a few weeks later. "Don't you have your own apartment? Why are you always here?" They were sitting, side-by-side, on the couch of his living room, watching some TV. Apparently, Okita was kicked out of Kagura's room to "focus more on studying".

"Nii-chan, don't call me that. Your sister doesn't want me in her room. So, here I am, waiting it out with you." Okita replied.

Another mystery. What was he always doing in Kagura's room? Kamui knew how she detested the Sadist, they must always be fighting whenever Okita was here. But if they were always fighting, why wasn't there any noise or exchange of insults? Maybe Kamui was just reading into it too much.

"Don't call me that, either. And what were you supposed to be doing in her room?"

Okita smirked. He held his chin, as if in deep thought. "Hmm, let's see." He started. "I tutor her."

And it made a bit more sense for Kamui. Kagura wasn't the sharpest knife in the drawer when it came to academics and Okita was definitely smarter than he was. But the way he said "tutor" sounded like he was implying something else. "Oh, that makes sense. I'm not paying you though."

The sadist chuckled. "That's alright. She's already on it."

Kamui hummed in response. There was no reason for him to be threatened about Okita, right? He always bought her dinner and he's even teaching her, there was no problem. But why was there something, an idea, gnawing at the back of his mind.

They spent the rest of the evening in an uncomfortable silence until Kagura came out to eat dinner.

X

"Kagura's going to love me for this." Kamui smiled to himself.

Abuto rolled his eyes and handed him the puppy that he dreadfully carried around town. Kamui found it somewhere in an alley and decided it would be a nice gift for his sister. "Alright, get on with it. I'll be off." Abuto said.

Kamui grinned and picked up the pup. He headed upstairs, already calling out to Kagura. When she didn't answer, he opted for her room. Now, Kamui knew that if his sister wanted privacy, the door would be locked. But since it fully twisted, he let himself in, only to be surprised at what he saw.

He was more than surprised. It felt like his eyes were going to pop out. They weren't really in the most compromising position, but, still, ideas were swirling in his mind. Kagura and Okita were sitting on the bed, with his sister situated between the Sadist's legs and his face buried in her neck while holding her wrists. Kagura, who was blushing like a tomato, was not fending off the male behind her. Their little moment was cut off when they finally realized Kamui enter.

"Aniki!" Kagura squealed.

"Ah, Nii-chan." Okita coolly said.

"Aniki―"

Kamui gently dropped the puppy, which ran towards Kagura, and held up his left hand. He pinched the bridge of his nose, clearly denying the reality of the situation, and rested his forehead on the doorframe. "Wait, my eyes are burning. Hold on a second." He gave out a long exhale and finally peeked at the couple.

The weight of his realization felt like he was carrying their refrigerator. He wasn't tutoring Kagura in academics, he was "tutoring" her in something else! And maybe that's why he never asked for compensation. Kagura was already "on it". He couldn't believe how ignorant he was to let all of this happen under his nose.

"Aniki, it's not what you think. We weren't doing anything… lewd!" Kagura blurted out the last word. She disentangled herself from Okita and headed for her brother who was now walking away. He headed for his room and locked it. Kagura kept on knocking but he wasn't answering no matter how she pleaded.

This was bound to happen, right? Kagura was no longer a little girl and he could no longer protect her from everything. But was it too much to ask that she stayed his little sister for a bit more time? If she was gone, then Kamui didn't really know what he was supposed to do after. All his life, he only knew of taking care of his sister, he was the one who knew exactly how to make her happy. Hell, he always spoiled her even when they were kids.

But maybe there were things she wanted that he couldn't give. Kamui was convinced that he would be enough for his sister because, definitely, she was enough for him. Kagura was already his sister and he felt that she was also like his daughter. How was he supposed to take it now that someone else was able to make her happy? And in such an indecent way, at that.

He let hours pass as he sat on the floor, leaning on the door, letting Kagura call him out until she got tired. He realized that it was already dark, judging by the lack of light from his window. Still in his sitting position, he reached for the doorknob to open the door. Apparently, Kagura was also leaning on his door because she fell on him, backwards.

"Are you still mad?" she asked, with tears threatening to come out.

Was he mad? At her, no. He wanted to be mad at himself, though. He felt that as a brother, he was lacking. He patted her head that was on his lap. "No, I can never be mad at you."

Kagura sat upright and hugged her brother by the neck, putting all her weight on his body. The sound of her giggles made him happy. That is, until Okita appeared above them, holding the puppy as it licked his face. "That means you're not mad at me, Nii-chan?" He plopped the puppy down. "I mean, she and I are like a package now. If you want her, you get me as well."

Kamui felt a vein pop. "Don't call me that. And I think that applies only to me." He pushed Kagura off of him, without noticing her annoyance, and stood up to eye-battle Okita. "And I don't approve of you, Mr. Pervert." Kamui's smile didn't hide his newfound contempt for the Sadist.

Okita could only smirk. "I don't really care if you do, as long as she approves of me, Nii-chan." It sounded like another sexual innuendo and Kamui finally came up with a solution to fend off the Sadist.

"Kagura," he smiled. "Tomorrow, you're losing your bedroom door. If you have to change clothes, do it in the bathroom. It's either that or I move into your room." He patted her hair once more before returning to his room, leaving Kagura, Okita, and the puppy in the living room.

She hit him on the arm. "You just cost me my privacy, you stupid Sadist!" She was heading for her bedroom when Okita pulled her back by hooking her arm.

"Then you just have to make the most of what privacy that's left for you." He hugged her by the waist and kissed the side of her neck.

Needless to say, all of them couldn't sleep. Especially Kamui. Maybe he should just remove the wall?

END

I didn't want to make Kamui a siscon, more like a fatherly-brother. This idea immediately came to me when you guys asked for a sequel, thank you for the inspiration! Reviews are much appreciated! Thank you for your time. Until the next story!