Naomi is a teenaged (roughly 16 or 17) girl. She has long black hair with a hime (princess) cut. She wears a standard seifuku with a long skirt that comes just above her knees, and black socks that come to the middle of her calves. She has a beauty mark underneath her left eye.
Naomi is a bold and strong-willed young woman, who never shies away from involving herself in a case, more specifically, ones that involve her older brother's well-being. Despite not being an ability user, she is often embroiled in the agency's conflict, but when told to leave, she mostly refuses.
As a Detective Agency clerk, Naomi is rather intelligent and quick-thinking, even amidst perilous circumstances. She is also shown to be mentally resilient because, in spite of being a near-frequent victim to kidnappings and ability users, she takes it quite well and is outwardly unaffected.
Probably one of Naomi's most prominent characteristic would be her deep-seated love for her elder brother, whom she is always with. When with her brother, she can be both childish and provocative. Her feelings seem to go beyond that of ordinary sisterly love and can be seen as romantic in nature due to a number of questionable circumstances and suggestive remarks. However, be it romantic or platonic, Naomi remains unwavering in her devotion towards her brother and does what she can to protect him from harm's way.
Besides her brother, Naomi is also kind and caring towards the other members of the Armed Detective Agency. She visibly shows concern when the others were contemplating abandoning Atsushi during his kidnapping and easily forgives him when he almost lost control of his powers.
Naomi is not an ability user and is therefore incapable of using an ability. However, she has immense endurance for a normal human being as she protected her brother from Higuchi's firearm assault using her own body, despite suffering major injuries.
Naomi lives alone with her older brother, Junichirou. Not much is said about their past or where their parents are.
Naomi was being taken as hostage by a bomber at their agency office. With the help of Atsushi and Kunikuda, the bomber was neutralized, but he managed to activate the bomb. Having no choice, Atsushi pushed Naomi away and covered the bomb with his body. When the bomb didn't activate, it was revealed all to be an act to test Atsushi. Naomi quickly hugged the bomber, who was her brother and overly excited how good he was while acting as the villain. She liked being tied and threatened and wanted them to continue that when they get home.
Later at a bar, Atsushi couldn't believe Naomi and Junichirou were siblings, but she assured him. Atsushi ended up having to guess the members' previous jobs and he guessed Naomi and Junichirou were students and they confirmed. As they received news about a client, they all went back to the office. Hearing the client request, Kunikida assigned Atsushi and Junichirou to the job and Naomi decided to join to, so she can be with her brother. As the client led them to a dead-end alley, she revealed it was a trap and started gunning them down. Naomi stood in front of Junichirou and protected him with his body, who then in anger fought the woman, but was defeated by Akutagawa.
- Naomi is named after the titular character of Tanizaki Junichirou's novel, A Fool's Love (痴人の愛). It can be thought that the anime Naomi's romantically active, rather promiscuous attitude is based off this, and other female characters that appear in Jun'ichiro Tanizaki's work.
- This makes her one of the only characters not named after an author, but rather named after a character from an author's work; Elise being another one.
- Bungo Stray Dogs merchandise, 2016 calendar, KADOKAWA