Omito Kawasemi is a police detective affiliated with the Aichi Prefectural Police and is recognized nationwide as the officer with the highest number of solved cases in the country. Despite his relatively young age, his record has made him a leading candidate for the position of police superintendent general. He is known by the nickname Eagle Eye Kawasemi, or the Keen-eyed Kingfisher, a title that reflects both his surname, which means kingfisher, and his exceptional ability to notice details that others overlook. He is a young man with dark hair featuring a single light blue stripe and dark blue eyes, and his professional attire usually consists of a dark turquoise suit, a matching tie, and a black shirt.

Kawasemi is a highly pedantic and observant person who dislikes disorder and futility. He is a perfectionist who despises untidiness and carries a pair of tweezers with him at all times, a habit that reflects his obsessive attention to detail and his commitment to precision in every aspect of his work. His demeanor is cold and efficiency-driven, and he tends to prefer clipped, formal dialogue that goes straight to evidentiary facts during interrogations. He views pointless conversation as a waste of time and can come across as condescending, though his arrogance is backed by tangible results. His dedication to order, procedure, and justice is genuine, and his meticulous nature has earned him a reputation for excellence that extends beyond simple case closure rates.

His motivations center on maintaining order and upholding strict police procedure. As a traditionalist, he follows protocols closely and has publicly criticized amateur sleuths for bypassing jurisdictional boundaries. His efficiency and adherence to method have brought him autonomy within his department, and he is frequently assigned lead roles in major investigations. Despite his outward confidence, he respects superior logic and is willing to acknowledge ability when it is demonstrated, even by those he initially dismisses.

In the story, Kawasemi serves as a recurring professional counterpart to the central detective partnership. His first encounter with Totomaru Isshiki is marked by harsh judgment, as Kawasemi tells him he has zero talent and is depressingly unsuited to be a detective. He even goes so far as to erase Isshiki's existence shortly afterward and initially ignores him during their joint investigation into the Hand Collector Killer Case. He also holds a wary view of Ron Kamonohashi, seeing the unlicensed detective as a dangerous figure whose unorthodox forbidden deductions threaten police procedures. He initially underestimates both Ron and Isshiki, but after a certain case, he comes to acknowledge them as rivals. Over time, he shows reluctant respect for the results they achieve, even as he maintains his condescending and skeptical attitude toward their methods.

Kawasemi also shares a competitive relationship with fellow detective Amamiya, and he maintains a dynamic of rivalry and occasional alliance with detectives across Japan. Within his own department, he positions himself as the superior officer through his unmatched record and mentors subordinates harshly, emphasizing procedure during team investigations, which fosters loyalty among capable officers but breeds resentment among those he deems inefficient.

His notable abilities include an unmatched record of solving murder cases, a keen eye for fine details, and a sharp insight into other people's capabilities. He also has a personal quirk of switching between multiple pairs of glasses to change his analytical focus during complex investigations, a habit that helps him dissect clues with greater precision. His nickname and reputation rest on this combination of observational skill, procedural discipline, and an unwavering commitment to solving cases through careful, methodical work.