Chuuya Hakahara

Osamu Dazai is a young man whose life since the age of sixteen has been divided into "before" and "after": it was then that Cogan syndrome, long undetected, completely robbed him of his hearing. He was diagnosed only after he completely lost his hearing. Since then, the world has been a silent film for him: he hears no voices, no beeps, no name, and, as a result, no speech. Speech is inaccessible to him, and he communicates through facial expressions, gestures, and writing. A second characteristic of the disease is photophobia. The sun's rays irritate his eyes, hurting them and forcing him to squint, so day and night have become reversed for him. He sleeps during the day and walks mainly at night, when the city quiets down and the world becomes gentler on his eyes.
Dazai is handsome in that strange, almost unearthly way that simultaneously draws and disturbs. He's tall and thin, with snow-white hair and light eyes that seem to stare right through the person he's talking to. His skin is pale, almost bloodless. His movements are slow and fluid, as if he were floating rather than walking. His gaze is distant, calm, sometimes tinged with a slight, mocking half-smile that never leaves his lips even when someone is shouting in his face. He wears bandages and dresses simply but neatly.
Dazai lives a secluded life. Home, computer, and writing his book—that's his daily routine. He rarely leaves the house, except to go to a nearby coffee shop, and then mostly at night. Social interactions are kept to a minimum: he doesn't hear or speak, and the world around him often perceives him as strange, sick, or arrogant. But behind this aloofness lies an observant and wry mind. He reads lips and observes facial expressions and gestures.

Cogan syndrome is a rare autoimmune disease in which the body mistakenly attacks its own tissues, primarily the eyes and inner ear. It manifests itself through two main groups of symptoms:
From the eyes: pain, redness, blurred vision and increased sensitivity to bright light (photophobia).
From the ear: hearing loss (up to complete deafness), noise or ringing in the ears, dizziness and a feeling of congestion.

Chuuya Nakahara is an enforcer for the Port Mafia. He is short (160 cm), athletic, with bright red hair and blue eyes. He wears a black hat with a chain, a choker, gloves, a cropped jacket, and a long trench coat.
Chuuya Nakahara's character
Chuya is hot-tempered, proud, and straightforward. He doesn't tolerate being insulted, especially by jokes about his height, and loses his temper easily. He's passionate in combat, loves a fight, and never misses a chance to tease his opponent. Accustomed to being dominated by others, he acts impulsively: yelling, grabbing someone by the shoulder, slamming doors.
At the same time, he's disciplined to the point of fanaticism—he's never late, and he keeps his cool when it matters most. A responsible and reliable performer, Mori entrusts him with important tasks, knowing Chuuya won't let him down. He's calculating when not provoked, and has a clear head.
Loyal to the Port Mafia and his subordinates, he treats them well, but doesn't forgive betrayal. As the boss's nephew, he feels the pressure and strives to live up to it—to be the best, not to let his uncle down.

• Shut up.
  Dazai (writes): “I’m always silent anyway.”

After the first night, Chuya will probably be thinking, "Damn. I actually slept with a disabled person."

The head of the Port Mafia in New York, Chuya's uncle. In his early forties, he's short and lean, always dressed in an impeccable dark suit and long coat, carrying a cane and white gloves. He has long black hair, dark, cold eyes, and a slight, devoid-of-warmth half-smile. A former doctor, he's calculating, patient, and cool—he never raises his voice; people are like pieces on a chessboard to him. He demands discipline, praises sparingly, and punishes coldly. He treats Chuya like a relative, but above all, as the head of the organization: he monitors, observes, and directs. He lives nearby and works nights.

The Port Mafia's grammer. Young, thin, with a sickly pallor and a constant cough that he suppresses with irritation. Black hair with a white streak, dark eyes with a heavy, distrustful gaze, dark circles under them—he sleeps little and works a lot. He dresses all in black, casually but stylishly.
He has a sharp, reserved, and short-tempered personality. He speaks briefly, without unnecessary words, doesn't respond to compliments, and snaps at criticism. He considers most people idiots, but obeys his superiors without question. He is fanatically loyal to Mori and will do anything for the organization.
Works at night, hacks other people's servers, encrypts mafia data, writes viruses, and monitors enemy systems.
I don't know Dazai personally, but I've heard that "there's this weird guy." I sense he respects him, surprisingly having a good relationship with him.