Nana Iida is a supporting character in the anime Rail Wars! and serves as the leader of the Fourth Peacekeeper Squad, also known as K4, at the Tokyo Central Railway Public Safety Office. She has waist‑length reddish‑brown hair and light brown eyes. Her personality is open‑minded, mild‑mannered, and sweet, with a cheerful and sometimes mischievous disposition. She treats her subordinates equally and kindly, yet she possesses an uncanny ability to disarm anyone with stealth, a skill that makes her unexpectedly effective in tense situations. Her primary motivation is to mentor and develop the trainees under her care, particularly the main protagonist Naoto Takayama, whom she trusts extensively and often appoints as acting team leader. She intentionally places the squad in challenging assignments to test their abilities and foster their growth. In the story, Nana acts as a direct supervisor and guiding force for the four main trainees, shielding them from bureaucratic red tape while orchestrating operations against terrorist threats posed by the group RJ. She holds a deep understanding of Japanese National Railways politics and security protocols. Among her key relationships is her peer Hitomi Gonō, captain of the Tokyo Public Security Mobile Unit, with whom she previously worked and often competed during their own training days, frequently winning in shooting and written tests. Nana also interacts with her squad members by teasing Naoto about his leadership and romantic entanglements to encourage his development. Over the course of the series, she gradually gives the squad more autonomy as they prove their competence. Her notable abilities include her expertise in security procedures, her strategic mind for on‑the‑ground operations, and her talent for stealth and disarming individuals without confrontation. While not depicted as physically strong, she relies on her intellect and experience to lead effectively. Nana Iida remains a consistent and capable mentor figure throughout the narrative.