Izumi, known as "Little Girl," is a 12-year-old middle school student. She lives with two maids from outer space, Mei and Ido, assigned to protect Earth from monster invasions. These maids reside in her home and serve her, but Izumi remains impassive towards their presence and eccentric behavior.

Izumi consistently exhibits a taciturn and emotionally reserved demeanor. She maintains a stoic expression, rarely engaging verbally or emotionally with the maids or the surrounding chaos. This detachment persists during the maids' antics, such as bath scenes or public transformations, and when encountering threats like a giant lizard monster; she shows no visible fear. Her routine includes cycling to school, though an incident occurs when her bicycle's brakes fail, causing her to crash into the monster. Threatened by the creature's multiple tongues, she is passively rescued by the maids.

After the monster is defeated and reverts to a seal-like form, Izumi participates in the crowd's efforts to encourage it back to water. She waves goodbye to the creature alongside the maids but displays no overt emotional investment. No background information on Izumi's family, origins, or personal history is provided. Her behavior remains unchanged throughout the narrative.