Kyoka Jiro trains as a hero student in U.A. High School's Class 1-A. Her Quirk, Earphone Jack, manifests as prehensile headphone jacks extending from her earlobes. This ability enables sound-based attacks and heightened auditory perception. She channels her heartbeat as vibrations through objects or equipment to create disruptive shockwaves and detects subtle environmental sounds for reconnaissance. Raised by musician parents Kyotoku and Mika Jiro, she inherited her mother's Quirk but chose heroism over their expectations to help others. Her childhood included musical training, initially perceived as separate from and embarrassing to her heroic path. Academically capable, she ranked seventh in Class 1-A's midterms. Her pragmatic and blunt personality often surfaces as snark, particularly directed at classmates like Denki Kaminari. She demonstrates loyalty to friends, notably Momo Yaoyorozu, and participates in social groups such as the "Bakusquad." Jiro exhibits insecurity about her appearance and interests, reacting strongly when excluded from Minoru Mineta's inappropriate comments about female classmates. Key developmental moments include: - **U.S.J. Incident**: Collaborating with Momo and Denki to defeat villains, using Denki as a conductive weapon and deploying sonic attacks via her Stereo Boots. - **Sports Festival**: Placing twenty-first in the obstacle race and participating in the cavalry battle, though her team failed to advance. - **Hero Names**: Adopting "Earphone Jack" as her hero alias during internships with Death Arms, assisting in hostage rescues by identifying threats through walls. - **Final Exams**: Partnering with Koji Koda against Present Mic. She devised a strategy leveraging Koji's insect-controlling Quirk, overcoming his phobia to secure victory despite sustaining ear injuries from blocking sound attacks. - **School Festival Arc**: Confronting her musical insecurities as lead singer for Class 1-A's performance. Mina Ashido praised her "husky and sexy" voice, validating her talents as heroic assets. This experience solidified her self-acceptance, leading her to later mentor Eri in music. - **Provisional License Exam**: Aiding Tsuyu Asui and Mezo Shoji in rescuing Momo from Saiko Intelli, emphasizing teamwork. - **Paranormal Liberation War**: Sustaining injuries fighting villains, including a scarred earphone jack. - **Final War**: Losing her left ear and earphone jack to All For One. She resisted his psychological terror, inadvertently triggering rebellion among his stolen Quirks. Post-battle, she utilized a prosthetic ear. Her combat abilities evolved through Ultimate Moves: *Heartbeat Distortion* shatters the ground via amplifiers, and *Counter-Balance* nullifies sound-based attacks. Her equipment includes forearm-mounted "Amplifier Jack" devices and Stereo Boots for directing vibrations. Post-graduation, she ranked as the No. 30 Pro Hero while maintaining her music career.