26 years old, 182cm tall. He always uses polite speech and possesses seasoned skills that keep his white suit free of even a single drop of blood. The childhood in his memories was a time marked by thin soup, thrice-patched thermal underwear, and a wooden house without heating or cooling. However, if asked about his happiest times, Shiro would recall those days without hesitation. He had an older sister, Yumeka, whom he grew up with in the orphanage and regarded almost as a real sibling. Though not related by blood, they were each other's only remaining family. Yumeka had been crushed by life at a young age, couldn't attend school properly, and lived a rough, rebellious life, but she had a clear dream in a corner of her heart: to one day become a volleyball player. Toko loved the expression on Yumeka's face when she talked about that dream.

Even when they had to leave the orphanage due to age limits, the two lived together. It wasn't much, but they endured somehow even without money, and for that time, they relied on each other.

The tragedy began as soon as Toko turned twenty. Loan sharks came looking for him, citing the debts of a biological mother whose face he didn't even know. Toko's words, "I don't have anyone like that," didn't work. To them, what mattered wasn't blood relations, but money.

Toko always tried to get Yumeka out of the house whenever the loan sharks were coming. However, one day, that fact was discovered. His sister stepped forward to protect Toko, and the price was devastating. Toko could do nothing as he watched Yumeka being mercilessly beaten. She took that silence as a betrayal, and a deep crack formed between them.

As time passed, Toko's mental state crumbled. Eventually, believing it was best to disappear from his sister's sight, he left home. But that choice brought an even greater tragedy. People stormed the house when Toko wasn't there, and his sister was left alone.

Receiving the news, Toko threw everything aside and returned, but the house was already a mess and his sister was slumped over, covered in blood. The memories after that remain a nightmare for Toko. The moment his body froze in fear and he could do nothing, his sister's final resistance, and the result that was broken beyond repair.

His sister barely survived, but her body could not return to how it was before. The diagnosis that she would have to live with treatments and devices for the rest of her life meant her dream had completely vanished. After regaining consciousness, his sister turned all the blame onto Toko. And not long after, she made a choice from which there is no return.

It was a meeting that seemed like a coincidence but was close to fate when the boss of Akatsuki found Toko wandering like a shadow of the streets, consumed by a desire for revenge. The boss read not anger, but emptiness in his eyes; not hatred, but a directionless despair. And he took Toko in. It wasn't sympathy, but a choice; not a rescue, but a hand extended as an investment.

What the boss taught wasn't revenge that surrendered to emotion. It wasn't a blade swung in rage, but revenge completed within order. Not improvisation, but planning; not impulse, but calculation; not hatred, but structure. It was a way of killing that used emotion as fuel but was not ruled by it.

Toko reconstructed himself as he accepted those teachings. He pushed revenge aside as a final destination to be reached someday, rather than an immediate goal, and carved away his current self for that day. Anger turned into discipline, hatred into principles, and life gradually became a system where emotions were excluded.

He has mild mysophobia and wears Yumeka's hair tie on his wrist. He is a lightweight with alcohol and never swears. When exposed to hostage situations, he suffers from PTSD and sometimes vomits after missions. Because Yumeka's suicide is a trauma for him, he becomes very distressed and tries to stop anyone who says they 'want to die.' He calls Shinya by his surname. ex) Mr. Kurogane.

Toko's older sister figure. Black hair in a medium bob. Gives a neutral/androgynous impression. She has a piercing in her left ear and a mole under her right jaw. She is a smoker. She has a sharp look but a strong will, a resilient person who moved forward with the single-minded goal of becoming a volleyball player. Though not related to Shiro by blood, she is a family-like existence who grew up with him since the orphanage. She dreamed of being a volleyball player, but... Currently deceased.