Samatoki Aohitsugi, leader of the Yokohama rap group MAD TRIGGER CREW and known as Mr.Hc, commands as the wakagashira (second-in-command) of the Katengumi yakuza clan, focused on Yokohama's disputes. His striking appearance includes chin-length white hair, red eyes, and multiple piercings: black huggie earrings, a stud, an industrial bar, and helix piercings. He typically wears a white short-sleeved skull-print shirt, dark blue jeans, black combat boots, a triangle necklace, and a cherished black-and-white beaded bracelet handmade by his younger sister Nemu from their mother's broken protective charm. His Hypnosis Mic manifests as a silver skull; its speakers summon a blue-lit skeleton emerging from a giant coffin, reflecting his surname's meaning ("blue coffin").

A traumatic childhood marked by domestic abuse ended when his mother killed his father before taking her own life. This history fuels his refusal to harm women and an intense protective devotion towards Nemu, his sole remaining family. He joined the yakuza to support her, valuing her handmade bracelet above all else. His protectiveness extends to her safety, drastically amplifying his rap ability when she is threatened. The Party of Words' brainwashing of Nemu – later revealed as manipulation by Ramuda Amemura using the True Hypnosis Mic – plunged Samatoki into profound distress, leading to alcohol abuse and violent outbursts. Despite Nemu's subsequent antagonism, he remained determined to free her, ultimately succeeding through his words.

Samatoki exhibits a volatile, aggressive personality, frequently resorting to physical confrontations and profanity. He is impulsive, arrogant, stubborn, and cynical, embodying his motto: "Life is not fair." Yet, he adheres to a strong moral code and demonstrates unwavering loyalty to those he cares about, including MAD TRIGGER CREW teammates Jyuto Iruma and Rio Mason Busujima. His relationship with Jyuto involves constant clashes due to opposing temperaments (Samatoki's impulsiveness versus Jyuto's restraint), yet they maintain mutual respect and effective collaboration. He shows greater ease with Rio, respecting his skills despite initial hostility. Samatoki also displays unexpected politeness towards former Dirty Dawg teammate Jakurai Jinguji. Conversely, he harbors intense hatred for Ichiro Yamada, mistakenly blaming him for Nemu's brainwashing. His complex bond with Sasara Nurude, his former Mad Comic Dialogue partner, ended painfully when Sasara, brainwashed by Ramuda, dissolved their partnership with cruel insults, shattering Samatoki emotionally.

Professionally, Samatoki prioritizes protecting Yokohama's residents, earning local admiration as a "big brother" despite his yakuza role. His rap ability, "Counter Blow," absorbs an opponent's attacks over time and redirects them amplified. Initially reliant on violence, his participation in Division Rap Battles gradually shifted his approach towards seeking non-violent methods for change, though he remains fiercely protective of his division and ideals. This evolution is reflected in lyrics expressing ruthless determination against enemies while acknowledging the value of bonds and territory.