Kyōma Katagiri is the older brother of Kyōka Katagiri and one of the four childhood friends at the center of the story, alongside Tohru Kazasumi, Kyōka, and Shizune Rindo. He is a serious and prideful individual, driven by a strong desire to prove his own power to the world. This pride manifests in a direct and often impulsive manner, and he shows little patience for those he perceives as weak or relying on personal charm rather than genuine ability. He is particularly critical of Tohru Kazasumi's worldview, dismissing him as someone who coast through life on likability, though he inwardly acknowledges Tohru's true capability and cannot afford to ignore him.

Despite his abrasive exterior, Kyōma is fiercely protective of his younger sister, Kyōka. His concern for her safety is so intense that he arranges for guards to follow her in secret without her knowledge. This overprotectiveness, however, is not fully reciprocated or understood by Kyōka, creating a one-sided dynamic in their relationship. He also serves alongside his childhood friends as a participant in the conflict between the two parallel worlds, Frontier S and the 17th Far East Imperial City Management District. Within this role, he shows concern for his comrades' mental state, as seen when he takes action to question Tohru's determination after the latter becomes shaken by the harsh realities of battle.

Kyōma's abilities are those of a capable gunslinger, matching the high-stakes combat required by Operation Stratos. Throughout the series, his development is tied to his interactions with his peers and his evolving understanding of the conflict, though his core traits of pride and protectiveness remain defining aspects of his character.