
The story was exactly as Kisuke had expected.
A branch family of the Naberius House was researching something forbidden and they coincidentally obtained a member of the extremely rare nekomata lineage, a nekoshou, there were even two of them. To be exact Kuroka and Shirone, who are now known as Koneko Toujou of the Gremory Family.
The master of the branch family and his aide took care of the two of them for the next few days until they offered a way for Kuroka to become strong. But they are shocked because she refuses and says that she only needs the safety of her sister, which is Kuroka's biggest mistake.
They use the excuse that Kuroka needs strength to protect Shirone in this dangerous world and she reluctantly accepts. At first, they had only done a few tests and exercises to gauge his natural abilities, but as time went on, they slowly increased to the point where he had to endure some physical trauma. This was all fine as Kuroka could see that Shirone had a peaceful and fulfilling time and would always spend time playing with her. She also never told Shirone and the abuse she received because she truly believed the moment was getting stronger.
Everything changes when they start giving Kuroka medicine after a few months of 'training'. Kuroka felt nothing in the first few sessions aside from her Demon Power increasing a little without her even doing anything. However, his opinion changed when they suddenly instructed him to lie down on the metal bed and fasten it very safely. When the new medicine entered his system, he felt an unbearable pain similar to someone repeatedly piercing his entire body. Kuroka shouted and thrashed wildly but she only saw the smiles of her master and aide. It was then that he realized that his good times ended here.
That day, Kuroka returns to her room and Shirone but she ignores Shirone who is waiting for her and anticipates their playtime. He went straight to his bed and cried himself to sleep. From that day on, he stopped playing with Shirone, not because he did not want to, but because the pain left after each session was too terrible that it was unbearable to move in the slightest. Kuroka did not want to let Shirone know of her suffering because she did not want to worry her and Shirone might even face a master who was not very good in their current position.
Kuroka naively believed that all of this would end one day and continue to persist. His strength seemed to skyrocket, but he learned how to shrink his abilities when they tested him. He did this because every time they knew his abilities were increasing and reaching a certain point, they would turn to stronger medicines. However, Kuroka could not hide her abilities forever as they strangely turned their attention to Shirone who gave her a bad premonition. He thought that if he did not improve, they would do the same to Shirone.
This would continue for a few more months and the relationship between Kuroka and Shirone became awkward. They still care about each other, but they rarely talk now. Shirone was just a child, so she was just throwing a tantrum.
On the fateful day when Kuroka killed her master and aide, they injected the medicine into Kuroka so powerful that it slowly melted her body and resulted in a pain she had never experienced before. He had already built up some resistance to the excruciating pain, but the pain from the last medicine was only testing his determination and vitality. The effects of the drugs subsided after a few hours but it made his life hanging by the thread and he pretended to sleep to rest a little but still had an awareness of his surroundings.
His master and aide actually thought that he was asleep because of his apparent weakness, so they started talking about their plans without moving into their usually heavily guarded rooms.
Kuroka heard them and was surprised by the content of their conversation. The master thought that Kuroka had already reached her limit, but their research was far from over. The adjutant then suggested to dispose of Kuroka and use her younger sister as her successor to continue their research.
Those words were the last straw that broke the camel's back. She did not care about her well-being and did not react much to being banished, but the safety of her younger sister, Shirone, did, at stake and she could not imagine her sister suffering the same pain she had at hand. Without thinking of the consequences, and overwhelming power flowed from within him even though his body was almost dying and managed to defeat the High-class Devils and his aides, killing them. But not until they can call in their reinforcements.
The force that was pushing him had already disappeared and he had to escape with Shirone. But he stopped and thought again, can you take Shirone with him? He did nothing, it was his crime and bringing Shirone with him would only make him an accomplice. If they were caught, Shirone would die with him. With the answer in his mind, Kuroka escaped alone with her weak body.
Luck would side with him as he could escape alive and also recover. But the same blessing did not apply to her younger sister as she was arrested as a suspect and immediately put to death.
He panicked and did not know what to do and would rush to the execution ground to save her even if she died while trying. It was there that he coincidentally met with Sirzechs and Grayfia who would also attend the execution as the representative of the Demon King.
Kuroka tearfully begged for their mercy and told them the whole story. Like any normal person, though, they would not easily believe one person's story especially on something as ridiculous as this case so they held a ceremony to read all his memories to confirm everything he had experienced. After the ceremony, both Sirzechs and Grayfia are convinced but even though they can help Shirone and bring her in, they cannot prove that Kuroka is innocent because they have no physical evidence. Memory-reading ceremonies were already banned a century ago and if others knew he was using them, his political opponents could take advantage of this point and attack him.
Sirzechs had no choice but to let little Kuroka escape after healing all her injuries as the higher-ups had already given a gift on her head. If there was no evidence to support him, he would not be able to save Kuroka as well as save Shirone who did nothing to help her sister kill their master to the limit.
"And that's how the SS class wants the villain Kuroka. I don't know where he is now because there hasn't been any news about him since." Sirzechs completes his narrative.
Rias clenched her fists while Akeno covered her mouth with her hands after hearing everything.
"Why!? Why not tell me all about this!?" Rias raised her trembling voice.
Sirzech's expression did not change and answered him simply, "Because you don't need to know about it. There's nothing you can do."
"T-But-"
"And that will only put you and Koneko in danger. You might even do something stupid like facing the Naberius Family." Sirzechs did not let him finish his sentence.
"..." - ".Rias could not say anything about it because she was really thinking of doing it.
"Huh..." Sirzechs sighed and faced Kisuke who was still smiling at him, "Good day, Urahara Kisuke. This is the first time we've met. I am Sirzechs Lucifer, the Demon King in charge of household affairs.
"Good day to you too. Urahara Kisuke, shopkeeper."
"..." - ".Sirzechs did not know how to react to it so he simply chose to ask what he wanted, "How do you know about Koneko's history?"
"I didn't know it. It was just my speculation that her older sister didn't really lose control as instructed."
"Hoooh... So you found evidence?"
"Haha... I wonder if it's proof, but it's not mine now and I can't give it to you." Kisuke replied with a laugh and thought, 'The evidence might be useful to me in the future, there is no way I will give it to you. And I really don't know about this Kuroka to help her. I only promised Koneko-chan to let her meet her.'