Ryouma/Kamui

It had started off so innocently. Ryouma saw that his sweet little sister had grown into a beautiful young woman.
“You’ve gotten big.” He commented.
Hinoka had immediately tried to hit him with her naginata.
“I was talking about her height!” He protested.
And he was sure that was what he meant. It didn’t matter that the way she moved was fascinating, both in and out of battle. It didn’t matter that when she hugged him, she would squeeze him a bit too tight. It didn’t matter that he could barely look at her when she’d just gotten out of the bath.
None of it mattered, he told himself. Kamui had finally returned to them, and Ryouma was going to fulfill his duty to her as his brother, regardless of any haunting dreams of her naked.
He’d nearly made himself sick the first time it happened. Even if he’d been a child back then, he still held her in his arms when she was a baby. It wasn’t proper for him to be looking at her like that.
And Kamui herself wasn’t helping the situation, either. She was very physical in showing affection. She opened up to him on her thoughts on fighting the people who had raised her. And she hadn’t managed to figure out how to keep her kimono tied up, so her breasts frequently peeked out.
After meeting with Saizou and Kagerou, Ryouma realized that he’d forgotten his sword in the bath. It wouldn’t do for him to be that careless in the future. With a sigh, he made his way to the bathhouse to retrieve it. As he did, he heard movement from the inside. He frowned, knowing that it was rather late and it was unlikely that anyone else would be taking a bath. He opened the door, bracing himself to face an intruder.
Instead, he found himself face to face with a naked Kamui as she was getting out of the bath.
For a moment, the two just stared at each other. Ryouma quickly apologized and shut the door. He returned to his room and sat down in the dark.
The situation was becoming absurd. He’d been so ready to have his younger sister back. He’d been so sure that they’d be a family, but he wasn’t sure how he could keep going. He didn’t feel this way with any of his other siblings. None of them haunted him like she did.
As Ryouma contemplated what to do, a knock came on the door.
“Enter.” He answered, and the door slid open to reveal Kamui.
He tensed up, but politely asked what the matter was when she sat down in front of him.
“I wanted to apologize for what happened in the bath.” She explained. “I was training with Kazahana-san until rather late, then I got sidetracked by an argument Hinata-san and Oboro-san were having, so I didn’t get to the bath until a short while ago.”
“It’s not an issue, Kamui.” Ryouma smiled at her. “Had I not forgotten my sword, you would have been able to finish your bath without incident.”
“Everyone makes mistakes, Ryouma-nii-san.” Kamui giggled.
The whole castle was quiet. It had been a long day of training and everyone had been eager to head to bed. It would take a lot of noise to wake anyone up.
This situation was dangerous.
“Perhaps we should both turn in?” Ryouma suggested. “We might be thinking more clearly in the morning.”
Kamui was still slightly wet, and the robe was clinging to her body in a way that made her figure quite clear to anyone who was looking.
“Maybe I want to stay with you tonight, Ryouma-nii-san!” Kamui laughed, and her breasts bounced ever so slightly as she did. “Sakura mentioned that she used to crawl in bed with you when she got scared at night.”
“That was when she was a little girl afraid of monsters that didn’t exist.”
“Oh? Are you implying that there are monsters here now?”
“Just one.”
“Where is it?”
Ryouma picked Kamui up and pushed her down onto the futon.
“Right here.”
He stared down at her.
“You know what you’re doing to me, don’t you?” He said coolly. “You’ve known all along, haven’t you?”
“Not at first.” Kamui admitted. “But it didn’t take me long to figure it out.”
“And you kept going.”
“You weren’t looking at me as a sister. I wasn’t looking at you as a brother.”
The confession eased some of the guilt gnawing on Ryouma’s heart, but not very much.
“No one can know about this.” He murmured.
“It’ll be our little secret.” Kamui smiled up at him.
The robe was the first thing that went. Ryouma wanted to get a better look at her body, and it did not disappoint. Her breasts weren’t quite as big as Kagerou’s or Orochi’s but they were quite lovely on their own. Her hips were a nice size, too.
“Do you like what you see?" Kamui giggled.
“I do.” He admitted.
“I’d like to see you, too.”
Ryouma quickly pulled himself off of her and removed his own robe.
“What do you think?”
“I’m certainly not complaining.” Kamui leaned forward and grabbed his already hardening cock. He shuddered as she started to wrap her tongue around it.
She was somewhat sloppy, and it was clear that she hadn’t done it before, but it felt wonderful. So much so that he had to stop her just a few minutes later, feeling like he would come right in her mouth if she didn’t stop.
“Are you saying you’re ready to put it in?” Kamui grinned up at him.
“Shouldn’t I prepare you first?” Ryouma gave her a confused look.
“I did it myself.” Kamui lay back to show him her dripping pussy. “Were you so focused that you didn’t see I was fingering myself?”
“Just a bit.”
He moved on top of her and slowly pushed himself in.
“Does it hurt?” He asked when she winced.
“Just a bit.” She leaned up and kissed him. “You can start moving now.”
It felt surreal. Just a few weeks ago, Ryouma would have done anything to have Kamui back so their family would be whole again. He’d never imagined they’d be doing this.
But here they were, kissing and making love like long-separated lovers.
It felt like hours were passing until he felt he was about to cum. It wouldn’t be proper for him to come inside, as tempting as it was.
Naturally, it was when he decided to pull out that he came.
“Ah!” Kamui gasped. “You… You came inside me.”
“I’m sorry, Kamui.” Ryouma panted as he kissed her. “I didn’t intend to, but I will take responsibility if anything happens.”
“I’m going to have you take responsibility even if nothing happens.” Kamui laughed.
She leaned up and kissed him.
“Kindly take care of me, Ryouma-nii-san?”
That was a promise Ryouma was more than willing to keep.