Izumi Murata is a high school student and the driver for the sidecar racing team representing Tsukuba Girls High School. She and her passenger, Nagisa Suzuki, form one of the rival teams competing against the main protagonists. Behind the handlebars, Izumi is known for her fierce and aggressive driving style, often cutting her racing lines extremely close to the edge to gain an advantage.

In personality, Izumi is depicted as having a queen-like demeanor, characterized by pride, selfishness, and a tendency to be overbearing. This dominant nature defines her relationship with Nagisa, which is explicitly described as a master-and-servant dynamic. This imbalance of power extends from their daily lives into their partnership on the racing circuit, where Izumi gives orders and Nagisa is expected to follow without question. This dynamic has been present since childhood, as the two have been in the same class since kindergarten, with Nagisa consistently acting as Izumi's follower.

The role of Izumi within the story is to represent one of the more extreme and dysfunctional, yet compelling, pairings that the series explores. Her narrative arc focuses on the tense and codependent bond with her partner. The pair embodies a sadomasochistic relationship, where Izumi's harsh treatment, including instances of physical aggression such as slapping and punching Nagisa, is a central point of conflict. Despite this apparent cruelty, Izumi does possess a degree of concern for her passenger, suggesting a more complex and conflicted interior life than her domineering exterior might imply.

A key development for Izumi occurs when she realizes that Nagisa’s mental state is beginning to change under the strain of their unbalanced relationship. This realization leaves Izumi herself at a loss, indicating a moment of vulnerability where her usual control is threatened. This internal conflict comes to a head when Nagisa questions the healthiness of their partnership. Izumi reacts violently but is immediately overcome with panic at the thought of a potential future on the track without Nagisa, revealing a deep, if troubled, dependency. However, despite this brief crisis, the fundamental structure of their relationship remains largely intact, reverting to its original pattern.

Her notable abilities are centered on her physical skill as a driver, demonstrated by her precise and aggressive control of the sidecar motorcycle. Her primary role in the narrative is to serve as a study in a highly dysfunctional partnership where dominance and submission are pushed to their limits, forcing both characters to confront the nature of their bond. The story explores whether such an extreme dynamic can function in a sport that requires absolute trust and synchronization between two people.