Midori Kodama, nicknamed "Jidama" by close friends due to her strong aversion to her given name, mirrors the protagonist's initial dislike for her own nickname. Her appearance features braids and spiky hair, paired with a consistent preference for practical clothing. She exclusively wears overalls in daily life, avoiding dresses except for traditional occasions like donning girls' kimono.

Personality-wise, she exhibits a tomboyish and aggressive demeanor, often intimidating male peers and establishing a "No Guy Wants an Amazon" dynamic in social settings. While not romantically interested in classmates, one incident involved her recalling the face of a home intruding thief.

Her family life centers on residing with her grandmother, sharing a generally close bond that fractured temporarily when she ran away and secretly stayed in Azuki's bedroom. Her mother, Aoi Kodama, works as a nurse and appears during a specific storyline. Their relationship involves neglect due to Aoi's demanding career, creating dilemmas between professional obligations and parental duties.

Character development includes family tensions sparking her brief departure from home. Another incident showcased her employing kid detective-style deductive reasoning to identify an intruder, reflecting situational behavior rather than enduring growth.