Earlier, before a bunch of delinquents jumped on Rito. A group of girls dressed in skimpy outfits can be seen. One of the girls, is Rito's sister, Kira.

They just finished buying clothes and were about to escort Kira to the subway when a group of students appeared in front of behind of them.

The male students were all known thugs at the school, one of them, their leader is a blue-haired brawn who casually licks his lips.

Usually, a girl would be petrified if they saw these students, especially if you're outnumbered. But Kira's group didn't even show no hint of fear, just a bit of surprise.

One of the girls, known as Minako took a step forward to the blue-haired boy. She was relatively beautiful although it was masked by make up. She had an ear piercing and a yellowish-dark hair. She had a stoic expression as she held two small luxurious handbags. 

"What is the meaning of this?" She asked.

The blue-haired boy then took a peek at the skimpy uniform Minako had. He took a long stare at the bulging cleavage the girl had before he licked his lips and turned to look at someone on the group.

"I want you and that girl to stay behind, the rest give us your money or we will break your pretty fingers and faces." The boy sniggered as the other male delinquents laughed.

Minako's face then went grim. She turned to look at the direction where the blue-haired boy pointed before a look of surprise filled her eyes. It was Kira that they wanted to stay.

Of course, she couldn't allow someone like Kira who has been a good friend of hers to be toyed at.

She then looked back at the blue-haired boy and started posing a seductive appearance, amplifying the view of her cleavage, she then seductively asked,

"Can't you just let them go~? It'll be fine if it's just me right~? I can take all of you boys at once, hehe~"

The group of girls especially Kira heard this and immediately got serious. Kira on the other hand, secretly got surprised at the sudden action of Minako before forming a small smile. She knew what her friend meant, sacrificing her own dignity for the sake of her own friend's safety was something she always respectfully adored.

But when Kira was about to stop Minako from doing it further, a slap can be heard.

The blue-haired boy arrogantly smirked as he gave a hard slap at Minako's face. 

"You bitch! You think we don't know how you run the game? This slut thinks she can just trick us. You there, come follow us quietly or..." He then violently grabbed Minako's hair, pulling it. Minako, who was in shock, naturally squealed in pain as she tried to struggle. "...we'll break her legs and let 50 boys rape her." He spoke at Kira.

The girls then started trembling in fear while instinctively trying to distance themselves from Kira. They didn't even bat an eye or even try to help their leader, Minako. They slowly reached out to their purses.

Kira on the hand, went full serious mode as a bunch of students slowly approached her. When suddenly, a shout can be heard.

"What the hell's happening there?"

On the distance from the group. A tall girl can be seen slowly walking towards their location.

When the various boys heard this, they immediately turned around, viciously glaring at the source of the interruption. The blue-haired boy arrogantly shouted back,

"Fuck off or we'll break your legs and rape you!" 

The tall girl flinched before trembling and running at full speed towards the boys.

The boys however, just laughed and arrogantly pitied the incoming figure. When it was visibly close, their eyes suddenly stared in horror as they realized the figure running towards them.

"K-K-Kaoru?!" the blue-haired boy nervously retorted as he felt the whole world weigh on him.

The various boys trembled as they instinctively dropped their weapons and started running towards the opposite direction of Kaoru. Even the blue-haired boy couldn't help but abandon the situation as he felt his own life becoming grim. They all sweated and made a full speed dash away from Kaoru. When the blue-haired boy was about to run, he suddenly was unable to move. Before even realizing it, he was already on the ground, both of his arms and legs tightly locked by another's. He went dumbfounded. Behind him, is Kira, deeply holding him in place. He tried to struggle but couldn't find a way out, everytime he tried to stand up, Kira's flexible legs or arms would tighten around him.

This was Kira's signature move, python lock. By constricting the target's movement with only minimal force and energy. All she needed to do was pin him down, climb behind his back and lock both of his essential body parts. Every struggle was like adding fuel to the fire, only by forcefully using brute strength could one possibly escape. Of course, she couldn't use it on people twice the size she is. But this was a very common move she used towards Rito.

The blue-haired boy noticed that Kaoru was already nearing, he then broke into tears as he shouted.

"P-Please!!! L-Let me go!! I-I'm sorry i will never do it again!!!! No!!"

Kira didn't mind his pleads as she waited for Kaoru to arrive. Meanwhile the girls earlier breath a sigh of relief then nervously stared at their leader, Minako, who was now glaring at them. She had a rather pitiable appearance, a disheveled hair and the dirty uniform.

She then turned towards the locked blue-haired guy before she angrily strode towards it.

Kira noticed her anger and just smiled.

Minako then gave a cold angry look at the crying boy before kicking his nuts.

"Ohhh! M-My balls...."

"This is for being an asshole!"

She then gave another kick,

"This is for ruining my hair!"

And another kick,

"For ruining my makeover!"

And kept going before the boy passed out.

Kaoru arrived and immediately asked,

"What was going on?"

Kira stood up, letting the unconscious blue-haired boy lay on the gutter. 

She then glared venomously at Kaoru before saying,

"Nothing."

Kaoru frowned as she heard the voice.

"Kira, you're causing trouble again. Don't think just because you have your sister protecting you doesn't mean the school can't punish you."

Kaoru then glared back at Kira. Their hatred eyes were glued to each other.

'This vixen thinks he can just seduce my brother.'

'How come Rito and his sister is so vastly different?!'

Kaoru and Kira thought.

Minako who was on the side listening suddenly jumped on the converaation with a worried look.

"Look Kaoru-sama, we didn't do anything, this guy's team jumped on us and were the one who rudely shouted at you earlier." She said as she pointed towards the unconscious boy.

Kaoru just took a quick glance at the boy before looking back at Kira.

"I know."

"Eh? T-Then..." Minako was surprised.

"...Just because you managed to fool him doesn't mean you can seduce him." Kira suddenly said.

"Seduce? I don't intend to do that when he just finally noticed me, even going far as to touch my body~!" Kaoru boldly declared as she revealed a smirk.

Kira got surprised before gritting her teeth. She wanted to say something in retort but could not let it out.

She couldn't just say 'I sucked my brother's cock while she ate my pussy.' in such a public place while her friends and classmates were there.

She could only glare and grit her teeth as Kaoru widened her smile.

"Well then, as your future sister-in-law, i'll overlook this matter and allow you off the hook for now." Kaoru arrogantly spoke.

"Don't get too cocky Kaoru!" Kira angrily shouted before turning towards the group of girls.

"Let's go! I can't stand a smelly skunk here!"

And with that they left.

Only Kaoru remained, smiling and blushing to herself.

...

Back on the present event.

"Oh. Um... You're busy, i see." Rito then slowly closed the door before a voice can be heard inside.

"Hey! C-Come in, you p-pervert." Kira blushingly spoke as she didn't even hide or deny her act.

Rito was quite shocked but he needed to know if she was alright so he entered back inside.

Meanwhile, Kizune was confused as she heard Ritovs voice upstairs. She was currently on kitchen, half naked and profusely masturbating as a bowl was placed under her wet streaming pussy. Catching liquids drooping from time to time. Her face flushed and her breathing ragged. In her hands, is an underwear, specifically Rito's.

'I wonder if it'll taste even better.' Kizune thought as she went back to masturbate.

Back on Kira's room. Rito slowly approached Kira. She then noticed the mood change despite her horniness creeping up to her.

"Is something wrong?" She worriedly asked.

"No.. It's just... Did something happened to you just now?" Rito asked back in a soft caring way. When he turned to look at Kira's face, he noticed that her expression went from worried to serious.

"Onii-chan, what happened to your face?" Her tone no longer worried as it was completely replaced with a commanding voice.

"That's not important, you didn't answer me, were you approached by male students from our school on the way here?" Rito dismissed her concerns as he caringly asked.

Kira then got surprised before answering,

"Yes there were some, but they ran away. I took care of one of them before a vix—" Suddenly, Rito hugged her head.

"Oh thank god, i was really worried. I'm so glad you're alright." Rito closed his eyes as he embraced the naked Kira.

Kira just went stupefied before the scent of Rito snapped her out of daze. She suddenly felt warm as she blushed and buried her head deeply intonhis chest.

"Kira, starting from now on, ride with your sister's car together with me. You must never go home alone again, okay?" Rito them carressed her hair.

Kira could only mutter in a soft weak tone, seemingly drowning in the love and attention she was given.

"Y-Yes..."

After some time, Rito finally let go of her but Kira at first didn't planned on letting go. Rito found it cute before he noticed, Kira was starting to breath roughly.

"K-Kira? Are you..."

And there, Kira raised her head revealing a lustful face as her hot breathe touched Rito's face. There was no trace of sister in her eyes, only the euphoria of heat.

"K-Kiss me....!" Kira then weakly said.

"H-Hurry up!"

"K-Kira! We need to talk about thi—" Kira then suddenly grabbed Rito's cock through his pants.

Rito tried to struggle but found out he couldn't stand up. He then looked back at her sister who was lost in pleasure screaming, 'Kiss me' repeteadly while rubbing his dick.

Rito scratched his head before sighing and saying,

"Ahh, whatever. I don't care anymore."

With that, he kissed her sister on the lips. Her eyes then rolled as she revealed a muffled scream. 

Rito was playing with her tongue as his hands moved on it's own and grabbed Kiravs breast. In the heat of passion, Rito suddenly got forceful and started french kissing her roughly.

He then pinned her on the bed as the muffled moans continued. Her body convulsing like crazy as she instinctively opened her legs, revealing her beautiful smooth slit, dripping with huge amount of liquid.

Rito then took off his pants, and started rubbing his cock on her pussy.

The kiss then broke off as Kira stuck her tongue out and said,

"Ahhhh~ Nooo~ Don't stop~ Ahhhh~ I don't care also~ I love you~ Impale me~ I love you onii-channnnn~!!" With that, her first orgasm arrived.

What a sensitive body!

Rito then positioned his cock on her hole before he slowly pushed it in. The intent of him trying to take his sister's virginity toppled over his sense of humanity.

And with final tug, he finally thrusted his dick deep inside her.

"Ahhhhh~!!!!!"