Leon/Kamui+Zero (Rough sex, mild NTR)

Prince Leon of Nohr made his way to the dungeon to meet his subordinate.

Zero had asked him to assist with an interrogation, and he'd accepted. The request didn't strike him as odd, as he'd participated in interrogations before, but he was puzzled when he reached the cell and there was no prisoner in sight.

"I'll bring them in in just a minute, Master Leon." Zero explained as he held up a pair of handcuffs that were chained to the wall. "I just need you to... put these on."

Before Leon's brain could process Zero's words, he heard a "click" and realized that he was now chained to the wall.

"Zero, what is the meaning of this?" Leon demanded.
"I just want you to hold back and observe for now, Master Leon."
"What the hell are you-Kamui-nee-san!?"

Leon was shocked to see his adoptive sister in the dungeon, particularly since she was almost naked.

"Why are you-" Leon gasped. "Zero, is she the prisoner!?"
"Correct!" Zero chuckled.
"Don't tell me... She was spying for Hoshido!?"
"Who can say?" Zero shrugged. "All I know is I'm going to be enjoying this."

Zero reached out and grabbed Kamui's breast. Kamui let out a cry of protest and looked at Leon in desperation.

"Nee-san, tell me you weren't spying for Hoshido." Leon pleaded with her.

His sister had vowed to stay with Nohr and end the war before it became too bloody. Leon firmly believed in her, and had promised to stay with her no matter what. If she were a traitor, Leon wasn't sure he'd be able to bear it.

"I-I... Ah!" Kamui moaned as Zero began to finger her pussy.

Kamui was beautiful. Leon had always known that, but it had only been recently that he'd begun to realize just how beautiful.

It wasn't until he released the breath he didn't realize he was holding when she chose Nohr that he'd been able to accept that he was in love with her. The thought of her being a traitor was terrifying.

And yet, there was something infuriating at the sight before him.

Kamui was protesting Zero's touches, but she was making not attempt to stop him. She was mewling like a kitten as Zero spread her pussy open.

And the fact that Zero had the gall to lay his hands on Kamui in the first place enraged him. He had no right to make those sounds leave her mouth.

Most of all, though, Leon was angry at himself for reacting to what was playing out before him. The sight of his sister being violated, pleasured by a man other than him, was arousing him. Would Leon really stand for it?

No, he wouldn't.

Zero had been careless. Leon could still reach his tomes. He murmured a spell, and the cuffs disintegrated.

"L-Leon!?" Kamui gasped.
"Zero." Leon's voice was low and dangerous. "Step away from my sister, or you die where you stand."

To Zero's credit, he complied immediately and calmly, exiting the cell without a word.

"Leon..." Kamui stared at Leon with an expression he couldn't read.

He pulled her toward him and smashed their lips together. He explored her mouth hungrily. His hands trailed down her back and squeezed her ass before moving to undo his pants.

"Nee-san, look." He said breathlessly, grabbing Kamui's hand and guiding it toward his cock.
"You've... You've gotten so big, Leon." Kamui gasped.
"It's because of you, Nee-san."
"Ah, so it's my fault. I should take responsibility."

Kamui turned her hungry gaze to Leon's face.

"Don't stop even if I start crying, okay?"

That was all Leon needed. He pushed Kamui up against the wall, lifted her leg and slammed into her. Kamui cried out, but there was something sweet in its sound.

"Congratulations, you two." Leon heard Zero call from outside the cell.
"What are you talking about?" Leon frowned.
"Leon, it's okay." Kamui smiled at him. "Zero was helping me."
"Helping?"
"I'm sorry for tricking you, but I wasn't sure how to get you to make a move." Kamui explained. "I asked Zero to help me."
"This was all a trick!?"
"Only to get you to make a move, Master Leon." Zero scoffed. "For a genius, you're rather dense when it comes to women. She's been practically throwing herself at you."

Leon let their words sink in. Then he narrowed his eyes at Kamui.

"I hope you like it rough, Nee-san."

Kamui shuddered and whispered,

"I want you to destroy me."

Leon slowly pulled out before slamming into her again.

"Ah!" Kamui moaned.
"You wanted my attention so badly you were willing to let another man fuck you?" Leon whispered into her ear.
"Don't be silly." Kamui said breathlessly. "I only let him grope me because I knew you'd react to it. I always intended to give my virginity to you."
"You seemed into it when Zero was touching you."
"Only because I was imagining it was you touching me."

Leon bit down on Kamui's shoulder.

"I still don't like it." He hissed. "I want to purge his touch from your memory. I want to fuck you so hard you can't even think about someone else."
"Leon, I can't see anyone else but you." Kamui protested.

Leon began to push Kamui up the wall, sliding out of her as he did so. Kamui let out a small whine, but stopped when Leon licked her breasts.

"Nee-san, do you love me?" He asked quietly.
"I do!" Kamui sighed in ecstasy. "I've dreamed of this for years!"
"How about Marx-nii-san? Do you love him?"
"Only as a brother. There are nights where just thinking of you makes me touch myself!" Kamui panted.

"What about you?" She asked. "Do you love me?"
"I've always been enchanted with you." Leon admitted. "I knew that one day you'd be stolen away by someone else, and I never understood why that made me angry. Lately I've been thinking of how to keep you with me."
"Tell me!" Kamui said eagerly.
"I've thought about coming inside of you over and over until you get pregnant."
"Just until I get pregnant?" Kamui giggled. "Besides, Leon, you don't need to do it over and over."

She reached out to stroke his cheek.

"Just come in me now."

She pushed herself down, pushing Leon in father. With a gasp, Leon released his seed inside of her.

They kissed once more.

"You two might want to clean up before heading to bed."
"Were you watching the whole time?"
"Just keeping an eye out in case someone came looking for you."
"I don't want to go to bed, though." Kamui protested. "At least, not alone."

It took some sneaking, but they were able to get Leon in Kamui's room without arousing suspicion.

"I think this might be the happiest moment of my life." Kamui murmured as she drifted off to sleep.
"Yes." Leon agreed. "Mine, too."

It took Leon some time to get to sleep. A part of him was afraid he was dreaming. Once he was able to understand that what was happening was real, he was able to fall asleep. His dreams were much sweeter than usual.