Naomi Tanizaki/Synopsis

Armed Detective Agency vs. Port Mafia Arc
Naomi is taken hostage by a bomber at their Agency office. With the help of Atsushi and Kunikida, 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 Café Uzumaki, 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. Later, she is presumed to be treated by Akiko Yosano after being brought back to the Agency.

While the Agency works on a request from a ministry officer, the Agency learns about Atsushi's kidnapping by the mafia. Though Tanizaki suggests they save him, Ranpo reasons out why they have no reason to do so. Worried for Atsushi, Naomi brings in the President himself to make a decision. In the end, Fukuzawa puts all work on hold and orders the Agency to help bring back Atsushi within three hours.

After the fight between Atsushi and Akutagawa at the cargo ship, Kyōka Izumi is brought to the Agency office, and Naomi is among the members playing with her. Atsushi, worried that someone like Ranpo might not forgive her crimes, soon finds out that Ranpo himself enjoys playing with her the most, even buying her some snacks.

The Guild Arc
As the Guild leader Francis Scott Key Fitzgerald and two members arrive at the Agency, Naomi serves Fitzgerald some refreshments. He marvels at the novelty of his chinaware cup, to which Naomi chidingly remarks that it came from their nearby ceramic store.

The next morning, Naomi accompanies Atsushi and Tanizaki to look for Kenji Miyazawa, who has gone missing after seeing the visitors out of the Agency building. Eventually, Naomi vanishes in plain sight, which is caused by the Guild's Lucy Maud Montgomery. As she brings them to her dimension, Lucy shows Naomi and Kenji imprisoned in her secret room. When Atsushi and Tanizaki later defeat Lucy, Naomi and the other prisoners are released after Lucy deactivates her ability and lifts the dimension.

After the incident, Tanizaki serves some baumkuchen to Naomi for breakfast. As Tanizaki reads the metropolitan police's records on Kyōka, he tells Naomi on how her parents were murdered.

Eventually, as the Agency, Port Mafia, and the Guild engage in a three-way war, Naomi and Kirako Haruno retreat into hiding in a safehouse. Naomi catches Haruno doting upon her cat named Mii-chan on her laptop; upon noticing Naomi at the side, she quickly returns to work. They then learn about a cruiser explosion near the Yokohama commercial port, which Haruno expounds to be owned by a private company. Naomi thinks that the company might be the Guild's and that the explosion might have been caused by someone from the mafia. Haruno then contacts and warns Fukuzawa, thinking that the Agency might be in trouble next, while Naomi hopes that her brother is safe.