Kazumi Suoh operates as one of two principal bodyguards for Ryūichi Asami, a formidable crime lord. He exhibits exceptional combat and firearms proficiency, routinely armed with a pistol and serving as the primary physical enforcer in Asami's organization. Suoh maintains a consistently professional bearing and appearance, characterized by a tall, muscular physique, short blonde hair, and a preference for formal suits. His loyalty to Asami is absolute, placing his employer's safety and objectives above all else. This dedication drives him to execute morally ambiguous assignments at Asami's command, such as the kidnapping of photographer Akihito Takaba during their first meeting. Suoh displays sustained coldness and distrust toward Akihito afterward, frequently noting that those opposing Asami typically meet fatal ends. He addresses Akihito formally with his full name, reinforcing emotional detachment.

When Asami's grandmother arrived unexpectedly at headquarters disguised in frail attire, Suoh recognized her instantly. He intervened professionally as an uninformed new employee attempted to bar her entry, addressing her with deference and personally escorting her to Asami's office. This episode highlighted Suoh's deep awareness of key figures linked to Asami and his adept handling of security lapses. While exact dimensions are unspecified, visual portrayals consistently position Suoh among the tallest characters in the series. His imposing stature complements his function as a physical enforcer.

Suoh's background, personal history, and character evolution across adaptations remain undefined beyond his established duties. His identity centers on his professional role as Asami's protector, combat expertise, and unwavering fealty to his employer.