Mitsuko Kongō is a Level 4 esper attending Tokiwadai Middle School after transferring from another institution, a move requiring a year of preparation. As heiress to the Kongō Aviation Industry conglomerate, her sheltered upbringing involved doting servants, leaving her unfamiliar with everyday tasks like navigation or cooking. Her distinct appearance features black hair with curtained fringes framing a prominent forehead, a well-endowed figure she openly displays during swimwear modeling, and her ever-present signature hand fan. Her initial demeanor displays pronounced arrogance and entitlement typical of an ojou-sama. This overconfidence frequently leads to comical failures, such as claiming culinary skill only to botch making curry. She habitually exaggerates her capabilities but ultimately admits shortcomings when confronted. This pride sparks friction, especially with Shirai Kuroko, whom she antagonizes early on. Beneath this facade, core traits emerge: protectiveness toward friends, kindness toward children, and a willingness to help those in distress, revealing underlying honor and decency. Mitsuko undergoes gradual social growth and humility. While retaining confidence in her aerokinesis ability "Aero Hand," she evolves from seeking recognition as Tokiwadai's ace to valuing camaraderie. She forms genuine friendships with classmates Wannai Kinuho and Awatsuki Maaya after initial posturing. A pivotal shift occurs during the Poltergeist Incident; she assists a defeated Misaka Mikoto despite prior rivalry and collaborates with Kuroko against MAR units to protect comatose children, fostering mutual respect. Her animosity toward Kuroko significantly diminishes afterward, leaving their conflict largely one-sided. Key involvements include hospitalization during the Poltergeist Incident, recovery enabling her participation in the Daihasei Festival ball-tossing competition, and later victimization by Kihara Yuiitsu's "Elements" during the heat wave crisis. Hospitalized again after severe injuries sustained defending others during the Daihaseisai incident, she reconciles with Mikoto during convalescence, expressing regret over past hubris while acknowledging Mikoto's inspirational impact. She eventually returns to daily life, humorously encountering a Misaka Sister. She owns a pet ball python named Ekaterina and resides in Tokiwadai's dormitory within the School Garden.