Kyouka Jirou trains as a Pro Hero student in U.A. High School's Class 1-A. Her Quirk, Earphone Jack, manifests as flexible plug-like jacks extending from her earlobes. These prehensile jacks stretch several meters under her control. By inserting them into surfaces, she channels sound vibrations—often her own heartbeat—to unleash offensive shockwaves or detect faint environmental sounds. Enhanced hearing grants her precise sound localization. Physically petite and fair-skinned, she sports chin-length dark purple hair with an asymmetrical sound wave-patterned fringe. Her triangular onyx eyes feature long lower lashes. Her hero costume evolves: initially, a black leather jacket, salmon ripped shirt, black pants, stereo boots, fingerless gloves, and red triangular face markings. Later iterations add forearm amplifiers, headphones, and chevron face paint. During the Final War, All For One destroys her left ear and jack, replaced by a flesh-toned prosthetic with a pink tip replicating her Quirk. Pragmatic and blunt, she often directs snarky remarks at peers like Denki Kaminari, masking underlying loyalty and protectiveness—especially toward Momo Yaoyorozu. Early insecurities about her appearance and rock-music passion faded after performing at the U.A. Festival. She exhibits fierce willpower, resisting All For One's psychological assaults. Combat relies on Quirk strategy over strength. Key techniques include seismic ground vibrations (Heartbeat Distortion), amplified close-range attacks (Heartbeat Surround), defensive sound barriers (Heartbeat Wall), and sound-quirk cancellation (Counter-Balance). Equipment includes Amplifier Jack wrist devices, stereo boots for propulsion, and her prosthetic. Academically high-ranking in Class 1-A, she demonstrates ingenuity, like synergizing with Denki Kaminari's Electrification during the U.S.J. Incident. Her parents, Kyotoku and Mika Jirou, nurtured her music interest but supported her hero path. At U.A., closest friend Momo Yaoyorozu partners in missions and band performances. Bonds with Denki Kaminari strengthen through battles, notably his focus on her during the Gunga Mountain raid. She motivates Koji Koda against Present Mic in their practical exam. Key development includes aiding evacuations at U.S.J., fighting in the Forest Training Camp and Provisional License Exam. Interning with Gang Orca sharpened reconnaissance. On Nabu Island, she battled Nine's forces alongside Mashirao Ojiro and Mezo Shoji. The Paranormal Liberation War scarred her right ear jack. In the Final War, resisting All For One incited rebellion among his vestiges. Post-graduation as the No. 30 Pro Hero, she mentors Eri in music, performs publicly, and uses upgraded gear.