Mina Toreishi, the youngest of the five sisters born on June 6, is twelve during the main events and thirteen in the later '95 timeline. Her youth manifests in a pronounced mischievous streak, often targeting her second eldest sister, Yayoi, with pranks and teasing. These inevitably provoke swift and severe retaliation, typically a well-aimed slap. Mina also displays a notably large appetite, frequently seen eating or snacking.

Within the squadron, Mina primarily serves as co-pilot, radar intercept officer, or "girl-in-back" for her fourth eldest sister, Uzuki, operating from the cockpit of Uzuki's large HB-04 multirole aircraft. This craft functions as a bomber, carrier, and supply vessel, requiring JATO modules for takeoff. Mina's personal aircraft, the HB-05 attack helicopter, is typically carried internally by the HB-04 and deployed mid-mission. Though usually partnered with Uzuki, Mina is qualified and does undertake solo flight operations in her helicopter.

Mina participates in both training exercises and combat missions alongside her sisters. During the Hummingbirds' debut engagement against rival idol pilot group SNAP, Mina and her sisters were initially contractually bound to act as passive targets in a simulated "turkey shoot." After SNAP's incompetence became apparent, the sisters abandoned this restriction and decisively defeated SNAP, eliminating all four opponents within a minute. Mina also took part in defensive actions against actual threats, such as intercepting invading aircraft over Tokyo Bay.