I'm sorry

Chapter 1: Shadows of the Past

The city lights flickered in the evening, casting long shadows on the streets below. High above, in a penthouse suite, Muichiro Tokito stood by the window, staring blankly at the bustling world outside. The weight of his past and present life bore heavily on his shoulders, manifesting in his cold, impassive demeanor.

Muichiro was only ten when his world shattered. Born into a wealthy family, he lived in a grand mansion with his twin brother, Yuichiro. Their parents were kind and loving, providing a safe and nurturing environment. One fateful night, however, that safety was brutally ripped away.

Muichiro could still recall the sounds vividly: the shattering of glass, the heavy footsteps echoing through the hallways, and the terrified screams of his parents. He and Yuichiro had hidden in their bedroom, clutching each other tightly. They had hoped it was all a nightmare, one they would wake from any moment.

But reality was far crueler. The robbers found them, and in the ensuing chaos, Yuichiro shielded Muichiro with his own body. Muichiro could still feel the warmth of his brother's blood, the way it soaked through his clothes as Yuichiro whispered his final words: "Stay alive, Muichiro."

Kokushibo, their estranged uncle, arrived too late to save the family but managed to kill the robbers. He found Muichiro, traumatized and clutching his brother's lifeless body. From that day forward, Kokushibo took Muichiro under his wing, not out of love or familial duty, but for his own nefarious purposes.

Under Kokushibo's twisted care, Muichiro was molded into a weapon, his emotions suppressed and his conscience dulled. Kokushibo partnered with Muzan, the head of the most ruthless gang and a powerful businessman. Together, they manipulated and used Muichiro for their dark ambitions.

As Muichiro stood in the penthouse, he heard the door open behind him. Kokushibo entered, his presence commanding and sinister. His piercing eyes settled on Muichiro, who remained unmoved.

"Muichiro," Kokushibo's voice was low and menacing, "we have a new task for you."

Muichiro turned slightly, his face devoid of emotion. "What is it?"

Kokushibo smirked, a cruel twist to his lips. "You are to eliminate Tanjiro Kamado."

A flicker of something crossed Muichiro's eyes, but it vanished as quickly as it appeared. "Why him?"

"He has become a threat to our operations. His interference with our plans cannot be tolerated. Do you understand?"

Muichiro nodded mechanically. "Yes, Uncle."

Kokushibo's smirk deepened. "Good. Ensure there are no mistakes this time."

As Kokushibo left the room, Muichiro's mind wandered back to the days when he and Tanjiro were inseparable. They were childhood friends, sharing countless adventures and dreams. The thought of killing him twisted something deep within Muichiro, but he quickly buried those feelings under layers of cold logic.

---

In a modest apartment across town, Nezuko Kamado sat on her bed, staring at a framed photo of her family. It had been months since the tragic death of her brother, Tanjiro, and the pain still felt raw. Nezuko was a kind and warmhearted girl, but grief had transformed her. Her once vibrant eyes now held a perpetual sadness.

She clutched the photo tightly, tears streaming down her face. "Tanjiro... why did you have to go?"

Nezuko's search for the truth about her brother's death had consumed her, but every lead had turned cold. Despair settled in her heart, and she struggled to find a reason to continue.

A knock on her door snapped her out of her thoughts. She wiped her tears and opened it to find her friend Aoi standing there, concern etched on her face.

"Nezuko, you can't keep doing this to yourself," Aoi said gently. "Tanjiro wouldn't want you to suffer like this."

Nezuko shook her head. "I can't help it, Aoi. He was my brother, and I feel like I failed him."

Aoi hugged her tightly. "You didn't fail him. But you need to take care of yourself too. Come on, let's go out for a bit. Get some fresh air."

Reluctantly, Nezuko agreed. As they walked through the city, Nezuko tried to distract herself from the pain. The lively streets and bustling people were a stark contrast to the emptiness she felt inside.

---

Back in the penthouse, Muichiro prepared for his mission. As he equipped himself with weapons and gadgets, his mind remained focused on the task at hand. He couldn't afford to let emotions cloud his judgment.

He made his way to the Kamado residence under the cover of darkness. The house was quiet, a stark reminder of the loss it had endured. Muichiro slipped inside silently, his movements precise and calculated.

He found Tanjiro's room and stood over his friend's sleeping form. Memories flooded his mind, but he pushed them aside, his hand steady as he drew his weapon. Just as he was about to strike, Tanjiro stirred and opened his eyes.

"Muichiro?" Tanjiro's voice was groggy with sleep but filled with confusion.

Muichiro's grip tightened on the weapon. "I'm sorry, Tanjiro."

Before Tanjiro could react, Muichiro struck, the blade finding its mark. Tanjiro's eyes widened in shock and pain, a single tear escaping as he whispered, "Why?"

Muichiro watched as the life faded from his friend's eyes, his heart a frozen wasteland. He quickly left the house, erasing any evidence of his presence.

---

The news of Tanjiro's death spread quickly, leaving Nezuko shattered. She sat in the living room, numb and broken. Her search for the truth intensified, but every clue led to a dead end.

As the months passed, Nezuko's determination waned. She felt like she was drowning in sorrow, unable to find a way out. Her friends and family tried to support her, but the void left by Tanjiro's absence was too vast to fill.

One evening, Nezuko received a message from Muichiro, inviting her over to study. She hesitated, but the thought of a distraction from her grief was appealing. She agreed and made her way to Muichiro's penthouse.

Muichiro greeted her at the door, his expression as cold as ever. "Come in, Nezuko."

Nezuko smiled weakly. "Thank you for inviting me."

They settled in his room, and Muichiro excused himself to get some snacks. As Nezuko waited, she noticed a book on his desk. Curiosity got the better of her, and she opened it.

What she found inside shattered her. Page after page detailed the victims Muichiro had killed, with Tanjiro's name prominently listed. The realization hit her like a physical blow, and she dropped the book, tears streaming down her face.

Muichiro returned to find Nezuko standing in the center of the room, her eyes filled with anguish. "Nezuko, what's wrong?"

She looked at him, her voice barely a whisper. "You... you killed Tanjiro?"

Muichiro's heart clenched, and he fell to his knees, tears of his own streaming down his face. "Nezuko, I'm so sorry. I never wanted to hurt him."

Nezuko's eyes were hollow, her spirit broken. She backed away slowly, unable to process the betrayal. "How could you?"

Muichiro reached out to her, his voice desperate. "Please, Nezuko, forgive me. I had no choice."

But Nezuko turned and fled, leaving Muichiro alone with his guilt and sorrow. He bowed his head, sobbing uncontrollably. "I'm sorry... I'm so sorry."

As the city continued its relentless pace outside, Muichiro was left to grapple with the darkness of his actions and the pain of losing the last shred of his humanity. The path ahead was uncertain, but one thing was clear: Muichiro's quest for redemption had only just begun.