Keith has dark teal eyes and brown, shaggy hair. He wears glasses and has a noticeable scar that runs from the bridge of his nose down under his right eye. His typical outfit consists of an unbuttoned jacket worn over a white button-up shirt, paired with slightly short slacks that leave his ankles exposed.

At the beginning of the series, Keith sports a messy, mop-like hairstyle and a beard. After his official transfer and first assignment with R.I.S. Unit 1.2, he cuts his hair shorter and shaves. However, following the conclusion of the Erika Flick case, he eventually returns to his original unkempt appearance.

At first glance, Keith appears to be a lazy and absentminded genius, but he possesses a sharp intellect that allows him to accurately predict his targets’ actions and plan accordingly. His mathematical skills are highly advanced, to the point where he can create detailed portraits using mathematical formulas. His obsession with solving problems is evident, as he once filled his entire room with complex equations.

Keith is short-tempered and highly values his privacy. Although he often acts independently during investigations, he recognizes when assistance is necessary, even if he struggles to ask for help. He has a fondness for Chicken Gumbo, a spicy dish made with ingredients from Hols Island. The traumatic loss of his adopted sister, Erika Flick, left a lasting impact on him, fueling his determination to seek justice for her death.

Following his retirement from the police force, Keith lives alone in an apartment within the city. He spends much of his time consumed by his investigations, covering the walls and floor with mathematical formulas and complex equations. His isolated lifestyle reflects both his deep obsession with solving mysteries and the lingering trauma from his sister Erika’s death.

Heath Kazama Flick
Heath Kazama Flick is Keith’s father. Throughout the series, their bond is portrayed as a warm and respectful father-son relationship, with Keith showing clear admiration and regard for his father’s intelligence and work.

Erika Flick
Erika Flick is Keith’s adopted younger sister. The two shared a close relationship during her lifetime, with hints suggesting Erika may have harbored deeper feelings for Keith, as implied by Gilbert Ross. Erika’s murder deeply traumatized Keith, leading him into a long period of obsession as he sought her killer. He eventually finds closure after confronting and defeating Gilbert Ross.

Gilbert Ross
Keith and Gilbert were longtime friends who understood each other well. Keith once described their bond by saying Gilbert would create puzzles, and he would solve them. Despite Keith’s growing suspicions that Gilbert was responsible for Erika’s death, he initially continued to interact with him normally. Their friendship deteriorated as Keith actively pursued Gilbert, while Gilbert, consumed by guilt, sought death at Keith’s hands to escape his suffering and be remembered within Keith’s mind.

Koku (Killer B)
Keith and Koku’s fates are intertwined due to events linked to the Jet Black Epitaph. As a child, Keith solved the Epitaph’s mystery, enabling his father, Heath, to create Koku. After the attack on the Jaula Blanca Research Institute and Heath’s death, Keith obtained his father’s notebook and used it to track Koku to Cremona. Throughout the series, Keith seeks Koku’s help to unravel the truth behind Erika’s murder. After earning Koku’s trust, the two develop a mentor-student relationship, working together to confront the forces behind Market Maker. After the case concludes, Keith offers Koku and Yuna a place to live with him.

Lily Hoshina
Upon meeting Lily, Keith notices an unsettling resemblance between her, himself, and his late sister Erika. Initially, he keeps his distance, partly because he finds her persistence annoying and partly out of a desire to protect her. Over time, however, Keith grows to respect Lily’s investigative abilities, even if her pushy nature continues to test his patience.