Disclaimer: I do not own High School DxD. This is made for entertainment purposes only.

Issei was lying on his bed with Rias and Asia taking both of his arms as they sleep. Just as Issei was about to get up, he can feel something soft inside of his blanket.

"Nyan…" A cat sound was heard underneath it, but Issei cannot respond as the girls took his arms.

"Wait a minute. This voice, this softness, and this body I remember very well." Issei said in his thoughts as someone suddenly came out from his blanket.

"Hello there, Sekiryuutei-chin. Remember me?" Kuroka emerged out of the blanket with a mischievous smile, much to the shock of Issei.

"Kuroka? Why are you on my bed? Just because you moved here doesn't mean you can do anything you want all the time." Issei whispered.

"Nyahaha. Come on Sekiryuutei-chin. I know how much you like oppai. Maybe after seducing you a little more, I will have some children to raise to save my species."

"C-Children? You can't just say something like that out of the blue! What if Rias, Asia, and Koneko-chan heard you?" Issei said out of panic though he continues to whisper.

"So let them. I don't mind having an affair." Kuroka lets out another mischievous laugh.

"Having an affair?" Rias said after waking up only to see Kuroka on top of Issei.

Asia also woke up and upon seeing Kuroka and Issei together, her eyes started tearing up. "What is Kuroka-san doing with Ise-san?"

"Don't worry. Sekiryuutei-chin will still be yours, but I also want to have children with him." Hearing this only made Rias angrier.

"No way. That service belongs to me." Before Rias and Kuroka can continue, Koneko appears in front of the door with a surprised face upon seeing her older sister on top of Issei.

"…Nee-sama. What are you doing in Ise-senpai's bed?"

"Hello Shirone. I am just here to piggyback off of Sekiryuutei-chin so I can have his babies." Again Kuroka makes a cat sound.

"…I told you that I am his future bride so I won't give that service to Nee-sama."

Kuroka laughed at Koneko's reaction as she continues to look displeased at her situation.

"All right, I guess I have done enough teasing for the morning. I am going to go get some breakfast. I will see all of you downstairs –nya."

After breakfast, Kuroka started training Koneko and Gasper yet again, but gets Issei more involved with her to test Koneko's concentration.

"Now what do you want from me?" Before Kuroka responds, she starts rubbing her breasts in front of Issei, causing Issei to lose his train of thought.

"How does that feel Sekiryuutei-chin?" Kuroka continues to tease him.

"Best feeling in the world!" Issei accidentally said out loud, causing Koneko to break her concentration and open her eyes.

"Nee-sama! I can't concentrate if you keep on doing that! Please stop doing this to Ise-senpai…!" Koneko realizes that Kuroka is unhappy and immediately gets back to training.

"You will never be able to concentrate if you can't focus. You know I was purposely doing that for your sake Shirone. If you cannot block your mind from distractions then the training is pointless." Kuroka gives a more serious face towards Koneko.

"…I am sorry Nee-sama. I will resume." Koneko then close her eyes and resumes.

"You don't have to be harsh to Koneko-chan you know? Being tough on her won't help fix your strained relationship with each other." Issei pointed out.

"Maybe so, but I prefer her to be stronger so the same incident that happened with our former master wouldn't happen to Shirone. Our relationship is definitely a tough sacrifice, but it is the one I have to give up so she won't endure the same things I have been through."

"You and Koneko-chan are not to blame. It was mainly your master's fault that things happened the way it did. Koneko-chan may have been blamed for the crimes you committed, but I know you never intended to make her suffer this much. Like I said before, I will help you fix your relationship with Koneko-chan. For right now, let's just give her some time to train." Issei smiles as he sees Koneko working hard.

Kuroka also smiles, knowing what is going on in Issei's mind. "I thank you Sekiryuutei-chin. I never actually felt closer to my sister before meeting you. It seems like you are good luck to everyone you get along with."

"Well I wouldn't say that." Issei blushed a little after hearing Kuroka's compliment.

"Nyahahaha. As long as I live here, I am going to rely on you somewhat to take care of me okay?"

Issei pats Kuroka on the head and nods, signifying a better relationship between the two, much to the ire of Koneko, who tries to resist opening her eyes and interfering. Due to a request involving Gasper and his homeland, Rias, Kiba, and Azazel leaves Japan for the House of Vladi in Europe. Issei is saddened seeing his girlfriend leaving, but remains optimistic knowing that she will return.

The next day after the group left to Europe, Issei saw Akeno making breakfast in Rias' place.

"Good morning Ise-kun. Did you sleep well?" Akeno asked.

"Yeah. I slept well despite Rias' absence, because of you and everyone else coming to my room. Thanks for trying to cheer me up last night Akeno."

"I should thank you. You have done a lot of things for me in the past Ise-kun. This is the least I can do for you. It was also quite surprising that you started calling me by name only, but I would like to continue to hear that from you if you don't mind."

"That's fine with me."

Issei then helps Akeno set up the table for breakfast and later saw a sleepy nekomata coming to the table.

"Nyaaaa. Good morning Sekiryuutei-chin. What is for breakfast today?" Kuroka yawns as she rubs her eyes. Le Fay follows her from behind.

"Good morning Kuroka. Akeno is cooking today. I don't know what she has cooked, but I am sure you will like it." Issei responded.

"I am sure I will." Kuroka becomes more fully awake and smiles.

"Good morning Sekiryuutei-sama, Akeno-sama." Le Fay said.

"Good morning Le Fay. You slept well last night?" Issei asked Le Fay.

"Yeah, though I am still anxious about the magicians who have interest in you. You are very popular among them."

"It is not an easy life being a Sekiryuutei. Imagine if you were in my place Le Fay. Would you be able to handle it?"

"I don't think so. That is why I admire you a lot. No matter how many times you were brought down, you always get back up."

"Thank you Le Fay. Let's all have breakfast." With everyone settled, they all begin enjoying their meal.

When Oppai Dragon airs on TV, Kuroka took interest in the show and begins watching with everyone else. Le Fay wasted no time settling, as she is a big fan of the show.

"I have been waiting for the new episode to come out for weeks. Glad they are airing another season." Stars form in Le Fay's eyes as she focuses completely on the show.

"All right! Switch Princess, I need another boost right now!" Oppai Dragon said in the show as Switch Princess comes to his aid.

Issei gets even more embarrassed as he watches his character powering up from Switch Princess' oppai.

"How much more embarrassing can this show get? I am already embarrassed from just reading the title." Issei said in his thoughts.

"Nyahaha!" Kuroka laughed out loud as she was watching, much to Issei's dismay.

"I can see why this show is popular with children, but this really makes me laugh –nyan."

"This is already embarrassing just watching this. Could you please not make fun of me since the character is based off of me?" Issei begged Kuroka.

"Sorry Sekiryuutei-chin, but it is fun watching you react like this -nya." Kuroka continues to tease Issei about the show.

With Ddraig asleep, he no longer has to suffer being called Oppai Dragon. After the show was over, Issei secretly whispers his jealousy that Ddraig can sleep through the whole thing. With no missions due to Rias' absence, the entire Hyoudou Residence decide to go out for some training with Koneko and Gasper again under Kuroka's supervision.

"How are the two doing?" Issei asked after he finished his training.

"They are both making progress, but it seems as though Gya-kun seems to be learning faster than Shirone."

"Probably because you tease her the most so she couldn't concentrate."

"I guess, but remember that she often gets more distracted so it is only fair." Kuroka pointed out.

"Have you thought of how you are going to reconcile with Koneko-chan?"

Hearing this surprises Kuroka. She becomes unsure of what to do and loses focus on Koneko's and Gasper's training.

"To be honest, I haven't thought about it yet. I wanted to reconcile with Shirone, but I don't know how to do it."

"Maybe you can start by having a real conversation with her. Try putting aside your thoughts of Koneko-chan's training and think about what both you and her like to talk about." Issei suggested.

"Maybe, but what is there to talk about?"

"Maybe you can catch up to lost times such as what you and Koneko-chan did after the incident. I know that you don't like revisiting your past, but you are going to have to accept that it has already happen or you are always going to feel guilty about it."

"Perhaps you are right Sekiryuutei-chin. If I continue to keep all of it inside, not only will Shirone continue to hate me, but I also will probably never get over this. I prefer that Shirone hates me for her sake and then I will finally be able to let go what happened in the past."

"I don't want your own sister to grow up hating you. Like I said, I will help you fix your relationship with Koneko-chan so I will be next to both of you."

"I swear if you continue to show this side towards every girl you meet, the entire female world will become your harem." Kuroka puts on a warm smile towards him.

"That is what I am aiming for in order to become the harem king." Issei said with confidence in an awkward way, causing Kuroka to laugh.

"You are pretty funny, you know that?"

"I was told by my parents that I often embarrass myself in every way possible. It seems that my parents are dismayed over my personality and doubts that I will ever become a groom. I decided to ignore their doubts and let them say whatever they want. That is until Asia and Rias suddenly moved into my house and they started showing my childhood photos against my wishes."

"This is actually the first time in a while that I am talking so casually to someone other then my own teammates. You really are a good influence on the inside."

"I am going to do a little training my self. I will see you after you are done with Koneko-chan's and Gaser's training." Issei heads downstairs to the training area as Kuroka watches over her students.

Kuroka soon finds herself unable to focus as her thoughts are on Issei. She starts blushing upon realizing. Koneko tried to sneak a peek at her older sister, but was immediately caught.

"Don't even think about it Shirone." Koneko immediately closes her eyes after hearing Kuroka's warning.

As Issei is training, a magic circle appears on the floor and out comes Grayfia.

Issei immediately trips upon Grayfia's sudden appearance. "Grayfia-san? What are you doing here?"

"With Rias gone to Romania, you are the one whom I can talk to for the time being about your next mission."

"Next mission?"

"There are sightings of a stray Nekomata who apparently has a grudge against Kuroka and is causing trouble in the Underworld. Rias may not be here, but it is your team that must stop him since he is of a dying race."

"I understand. I will alert everyone at once." Issei heads out of the training area as Grayfia disappears.

Once after everyone is alerted, Kuroka and Koneko begin to get worried, hinting they may know something about the stray Nekomata. Issei takes notice of this, but both said there is nothing wrong. Everyone teleported to the Underworld only to fins that the Nekomata is training in a barren area filled with nothing but large boulders. He takes notice of the Gremory Group and the girls of the Vali Team who came along with them and get furious, revealing a quarter of his face scarred.

"So Koneko and Kuroka finally show up. I see that you have brought the Sekiryuutei along with the rest of your friends. Good, because the more I can kill the better."

"I knew it was you Keita. I first thought you died in the turmoil when I saw your beaten body." Kuroka responded with a serious voice.

"This is something that you caused when you killed your master. I was taking a tour in the Underworld when all of a sudden an explosion happened next to me, burning the part of my face you see now. When I woke up, I saw a dead body next to me and you leaving with blood on your hands."

"I was only merely trying to protect Shirone."

"If that is the case, why was your sister nearly executed? Yes, I have done my research after I came back home. I feared you at first, but because how everyone has treated me because of this scar, I ended up hating you more and more as I got older. This is my time for revenge so I will not let you escape this time."

Hearing this shocked Kuroka and Koneko. Kuroka then turns to her younger sister with a sad face before turning back.

"I didn't mean for any of this to happen Shirone. I wanted to protect you, but instead you ended up getting blamed for something I did. I didn't want him to experiment on you so I killed him. I am sorry."

Kuroka prepares for battle, but Issei stops her and talks to Keita instead. "I can understand that you hate what Kuroka has done to you, but it was an accident. Let's just heal the scars and fix the problems created by the incident."

"It's too late for that Sekiryuutei. I have already lost something I can never get back. If you dare to interfere, I will kill you."

"What exactly did you lose that was so important to you?"

"My mind. After I came back, I was subjected through numerous and extreme medical procedures and experiments to the point where I don't recognize myself and the world that I live in. They wanted to see whether they could use my scars to find who did this, which is why no one bothered to heal me. Kuroka made this and I am here to return the favor. There is no talking your way out of this you two Nekoshou. I will make sure your race goes extinct."

Keita begins using Senjutsu and aims its power towards Kuroka. Kuroka dodges the attack, but another suddenly hits her.

"What is this?" Koneko asked.

"The Nekoshou are the strongest of all Nekomata so I trained nonstop so I can surpass both of you; knowing that you haven't fully mastered your own abilities yet. At last, I can finally have peace after I kill you two." Keita uses Senjutsu again and aims at Koneko, but Issei blocks the attack with his Boosted Gear.

"I see that you are going to interfere. No matter, I will kill you all just the same."

Irina and Xenovia both summon their swords, but were easily dispatched as Keita heads towards Issei at supersonic speed.

"Fast." Issei blocks his punch, but was thrown backwards.

"If only Ddraig was awake, I can beat him." Issei struggles to get up, but was given a pat on the shoulder by Akeno.

"Ise-kun, remember that we are fighting together. Try not to do things on your own okay?" Akeno smiles as she transforms into her miko outfit.

"That's right Akeno. Let's fight together."

Akeno summons her Holy Lightning towards Keita, but he activates Youjutsu, creating illusions, thus sparing himself from Akeno's attack. All of the illusions, however, were destroyed after Issei uses Dragon Shot.

"You will never beat me at this level." Keita blasts Akeno away using Senjutsu and ends up doing hand to hand combat with Issei.

"As expected from the Sekiryuutei. You are strong, but yet you still refused to activate your Balance Breaker?"

"That is none of your business!" Issei attempts to strike Keita in the head, but the latter easily dodges by moving his head. He then grabs Issei's head and slams it down with full force, causing the ground to break.

"Big mistake." Keita said to Issei.

Koneko then fights and got Issei to boost her strength despite her injuries. Unfortunately, her Senjutsu is inferior compared to Keita's and was overwhelmed.

Akeno struggles to get up, but holds her arm. Issei takes notice after recovering from Keita's attack.

"Akeno, are you okay?"

"His attack may have disabled my ki. It looks like I won't be able to use my powers for a while until my arm heals."

"Until then, I will give you some power." Issei then transfers some energy to Akeno, allowing her to use her Holy Lightning, but is limited to how much power is given to her.

Le Fay summons her golem, Gogmagog, but the golem is so slow, that he wasn't able to keep up with Keita's attacks and was knocked down after punching the Golem using Senjutsu. Just as he was about to kill Koneko, Kuroka intervenes and uses Senjutsu of her own to push Keita back.

"Don't leave me out." Rossweisse gets involved in the battle and begins using bombardment spells, but Keita catches Kuroka using a surprise attack and holds her hostage. As soon as she cancels her attack, Keita immediately strikes her before she can cast a defense spell to block it.

Using Kuroka as a hostage, he severely disrupts her ki to prevent her from fighting back. Both the Gremory Team and Le Fay took a step back seeing this after Asia heals Akeno.

"Bring Koneko here. If not, I will kill her immediately right now."

After a brief silence, Keita prepares to kill Kuroka, but Koneko steps out and ambushes him. It turns out to be another illusion from using Youjutsu as Keita immediately uses his Senjutsu infused punch and hits Koneko. Angered by this Kuroka, combines both Senjutsu and Youjutsu and blasts Keita, freeing herself from being his hostage. It turns out to be another physical illusion created just in case the hostage negotiation fails.

With Issei limited to using Dragon Shot as his only offensive move, all he can do is boost the power of his teammates, which is shown to be ineffective as they are being overwhelmed with Keita's cunning and resourceful strategies.

"He obviously is more skilled then Koneko-chan and Kuroka. I need to find a way to get past his guard." Issei then moves behind the boulders to observe the battle.

Ravel provided covering fire using her flames to protect her team, knowing that Keita is stronger than she is. This had little effect as it did distract Keita from harming her more injured teammates, but he eventually found his way around the flames to continue his assault, causing Ravel to retreat.

"This is bad. I better call Onii-sama for help." Koneko stops Ravel after she got up.

"…They won't make it in time. We just have to find some way to defeat him." Asia begins Koneko's healing treatment.

"Hauuu. What can we do to defeat him?" Asia is getting even more scared every minute as they continue fighting.

"There is no way I am losing to you if this is all you got." Keita strikes down Xenovia and aims his Senjutsu attack at Asia, but Rossweisse defended Asia from the attack.

Seeing Keita distracted, Kuroka uses Senjutsu to control space and aims at ambushing Keita. Because Keita is a Nekomata himself, he senses the attack and uses the same technique to negate it, shocking Kuroka. Seeing that her own skills are inferior, she then charges at Keita in hopes for an ambush, only for him to kick her out of the way.

"You are annoying, but I will have fun killing you." Issei taps on his shoulder before Keita lands the finishing blow.

"Don't you dare harm my friend!" Issei grabs his arm and aims his Boosted Gear right in front of him. Unable to defend himself on time, he took on Issei's Dragon Shot with his own body and his body was sent up an enormous mountain spotted near the area. Keita is finally defeated and restrained before Grayfia comes to take him away.

"I am sorry that I had you deal with him. We know how difficult it must have been without your team leaders, but many couldn't be contacted and you were one of the few that can respond. I will make sure to have this Nekomata severely punished for his crime."

"Wait Grayfia-san, this man wasn't fully at fault and therefore doesn't need to have severe punishment imposed on him."

Kuroka immediately becomes surprised of Issei's sudden request for mercy. "What are you doing Sekiryuutei-chin?"

Koneko also questioned Issei. "…This man tried to kill us earlier in our battle. What is the reason for showing mercy?"

"If you take a look closely, you can tell that his mind is not straight. After all that he has been through, punishment will only make it worse. Plus, he is also a Nekoshou like you. It will be bad if another is gone since the species are dying out. Grayfia-san, did he commit any other crimes before this?"

"He was not a criminal prior to the battle according to the records. You definitely have a point there, Ise-san. I will look more into it if I can. We will have him sent to rehabilitation for treatment and hopefully cure him. I thank you for accepting my request so enjoy yourselves for today." Grayfia then disappears with Keita though a magic circle.

Back in the Hyoudou Residence, Kuroka and Koneko began conversing with each other for the first time since the incident that nearly got Koneko executed. Seeing their progressing relationship, Issei heads towards them.

"Looks like you two are finally getting along."

"It's all thanks to you Sekiryuutei-chin –nya."

"So what were you two talking about?"

"What you suggested. We are catching up on lost times –nya."

"…Nee-sama is currently telling me how she got to be a part of the Vali Team and plans to talk about what she is trying to do to get herself off of the most wanted list in the Underworld."

"Looks like she just wants to live a normal live." Issei added.

"Hey Sekiryuutei-chin." Kuroka called out.

"What is it Kuroka?"

"When I was about to be killed by Keita, you suddenly came along and beat him, but I also heard you say something before you landed the attack."

"Don't you dare harm my friend!" Issei suddenly remembered saying that before landing the finishing blow.

"Did you really mean that? Do you really consider me to be your friend?" Kuroka's face turns a little red.

Issei smiles. "Anybody living in this house is not only my friend, but also my family. It took me some time to get used to your presence when you first moved, but you are now family. That makes you just as important to protect."

"T-then it makes me glad that I am allowed to stay here." Kuroka stutters a little as she turns a little more red, much to the shock of Koneko and Issei, who have never seen that side of her.

"Kuroka is almost like Akeno and Rias in a way. She has totally gone from a cat to a normal girl. She is dangerously cute." Issei said in his thoughts.

"By the way, you didn't activate your Balance Breaker. Did something happen?" Kuroka asked.

"Ddraig is asleep as he used too much energy during the crisis in the Underworld involving the Khaos Brigade. I won't be able to activate Balance Breaker for a while as long as he is asleep."

"When do you think Ddraig will awaken?"

"I don't know too much about dragons, but because he is a Heavenly Dragon, it is probably going to take a long time before he can get back to his normal state. I am still trying to figure out what are the alternatives to get his energy back as Ophis is weakened and is not able to transfer energy."

"I see. Until then, we will just have to take care of ourselves. You are still able to use a little of its power so its not a total loss –nya." Kuroka returns back to her old self.

"It will be much better once Ddraig wakes up, but I agree. At least I am able to do something in that battle as long as I don't have to face anyone as tough as the Khaos Brigade."

"The Vali Team is no longer your enemy so remember that we can also help if needed Sekiryuutei-sama." Le Fay added.

"I know and I am very thankful for that. I will be relying on you two as well as my own team. Whatever comes our way we will be ready." Everyone heard Issei's speech and smiles at his determination.

Ophis suddenly comes out from behind the sofa. "I, fell asleep for one hour."

"How did you fall asleep on the hard floor for an hour? Why were you even behind the couch?" Issei continues having these thoughts due to Ophis' sudden appearance.

With Issei distracted, Kuroka walks towards him and gives him a kiss in the mouth in front of everyone, much to their dismay as Issei's face turns red.

"…N-nee-sama! What is the meaning of this?" Koneko stutters seeing Kuroka kissing Issei.

"It turns out that I really do want his children. Sorry Shirone, but I am going to make him my groom as well –nya." Kuroka then embraces Issei and pushes her breast onto his chest.

"This feeling truly is the best. Wait! This isn't the time for that!" As Issei looks around, most girls began staring at him with jealousy with the exception of Rossweisse, Ophis, and Le Fay.

"I won't allow it!" Xenovia said.

"There is no way I am losing Ise-san to someone else." Asia said.

Everyone started making jealous remarks with Koneko making the first move. "Please get off of Ise-senpai! I will not allow Nee-sama to be his bride!"

Koneko attempts to separate the two, but Kuroka easily pushes her off. All the girls that are in love with him then attempts to do the same.

"I am so glad that Rias isn't here to see this." Issei again said in his thoughts as he becomes the victim again.

Hello everyone. Sorry it took me a long time to make the oneshot of Kuroka's entrance to the harem. School and writer's block prevented me from progressing. The release of Volume 14 of the Light Novel forced me to change some of the ideas. This fic takes place between after Kuroka's and Le Fay's move to the Hyoudou Residence to before Issei's battle with the stray magicians. I will still be working on the other fics so look forward for more. Sorry it is shorter than Sona's oneshot, but I feel that this is slightly better as it is not as excessive.