Sure! Here's the translation:
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After the meeting ended, the atmosphere at the Hashira headquarters felt tense. Each of them quickly returned to prepare for the impending battle. Shinobu walked towards the laboratory, where she had spent time researching a medicine that could turn demons back into humans alongside Tamayo before.
The laboratory was a unique room filled with various rare and exotic plants. Among all the plants, the wisteria flower dominated, known for its deadly poison to demons. Shinobu was skilled in concocting various types of poison from the wisteria flower, and at that moment, she skillfully poured a mixture of different poisons into a hidden mechanism in her Nichirin sword. Only she knew how many types of poison she had stored in that weapon. There might be dozens, perhaps even reaching a hundred.
However, as she contemplated her plan to face Doma, one of the strongest members of the Twelve Kizuki, anxiety began to cloud her heart. She knew that the toxicity of the poison she had concocted might not be enough to kill Doma. This doubt made her frown. With a resolute determination, she decided to take a more extreme step.
Shinobu lifted a syringe filled with the wisteria poison she had concocted. She took a deep breath, calming herself before injecting the poison into her own body.
"I will make myself a poisonous weapon," she whispered to herself. In her mind, she was determined to kill Doma. If she were to die in this battle, she wanted to ensure that Doma would also die. She was not worried that Doma would consume her body because, according to the information given by Haru, Doma would only eat women.
Meanwhile, on the other side of the headquarters, Haru felt an inexplicable unease. The feeling of restlessness grew stronger. He felt as though something important was about to leave him. His thoughts raced, and he eventually realized that the only thing making him anxious was Shinobu.
During the more than two months he had been in this world, the bond between him and Shinobu had grown closer. They often spent time together, and it was unavoidable that he had feelings for Shinobu. Nevertheless, he knew that expressing his feelings was not a wise choice.
He was a reincarnator, and this world was merely a stop for him. After completing his mission, he would have to return to his real world, and Shinobu likely wouldn't be thinking about romantic feelings.
Without hesitation, he decided to search for Shinobu. He wanted to ensure that she was okay.
After searching around, Haru finally found Shinobu in the laboratory. He saw Shinobu injecting poison into her own body.
"Shinobu!" he exclaimed, surprised and worried. "What are you doing?!"
Shinobu seemed startled to hear his voice, but then her face returned to calmness. "Haru, this is none of your business," she replied, trying to sound firm. "I'm doing this to kill Doma."
Seeing Shinobu like this, he knew what choice she had made, and he wouldn't let it happen.
"Shinobu, stop! You don't need to hurt yourself to kill Doma. With me and the other Hashira, we can definitely defeat him," Haru said firmly as he took the remaining poison from Shinobu and threw it away without hesitation.
He stepped closer, taking Shinobu's hand. "Shinobu, listen to me. I don't want to lose you. I don't want you to sacrifice yourself like this."
Shinobu was taken aback by the sincerity in Haru's eyes and his sudden confession. She had never thought about any romantic feelings before. But right now, all her memories flowed slowly like a film in her mind. Unknowingly, Haru had entered her life.
"Haru, I...," Shinobu's voice trailed off.
Haru pressed his lips against Shinobu's, giving her a kiss, as if conveying how much she meant to him.
Shinobu was shocked by Haru's kiss; her mind couldn't respond for a moment, allowing Haru to dominate her.
After a moment of realization, Shinobu slowly pushed Haru away and looked at him with complicated feelings. Although she didn't know much about love, she was grown up enough to feel Haru's love for her. She didn't know how to respond; she currently had no interest in pursuing a romantic relationship, not until the demons were exterminated.
"I know you currently only want to kill Doma and all the demons and don't want to pursue any romantic relationship. But please don't take your life lightly. I don't want to lose you. Promise me to live as strongly as you can. I'm sure Kanae wouldn't want to see her beloved little sister die. I'm sure she wants you to be happy," Haru said gently.
Shinobu felt her heart race. Haru's words pierced her heart like a sword. She knew that everything Haru said was true; she understood very well what kind of person her sister was.
"Stop thinking that you have to bear all this burden alone," Haru continued. "We are a team. We fight together. If you fall, I will be by your side. We can get through this together."
Shinobu stared deeply into Haru's eyes, trying to find honesty in his words. She saw strength and sincerity in Haru's gaze. Finally, after a moment of taking a breath, Shinobu felt the walls that had been blocking her crumble.
"I don't know how to trust my life to someone else," Shinobu said with a trembling voice. "But... I don't want to lose you. I don't want to regret anything."
Haru smiled and said confidently, "We will get through this together, Shinobu. We will definitely kill Doma and all the demons."
After that, Haru suggested to Shinobu to use the potion prepared for Muzan in this battle, but with a reduced dosage so as not to raise Muzan's alertness. It was then that Shinobu realized she had been too impulsive and made extreme decisions driven by her hatred for Doma, so she hadn't thought of something as simple as that. With a clear goal, they worked together all night to reduce the dosage of each potion. Although it was still the same potion, the effects would be weaker due to the reduced dosage. For example, the potion used to turn demons into humans now could only provide a debuff overall, both in regeneration, speed, and strength.
In addition to that potion, Shinobu also prepared a chain poison that would continue to develop new poisons after various types were injected into Doma's body. This poison would be used after various attributes of Doma weakened to avoid Doma developing immunity to the poison, as in the original work.