Harumi Kiyama is a former researcher from Academy City's Advanced Education Department, originally working under Kihara Gensei. She possesses long wavy brown hair and prominent dark circles under her eyes, a consequence of chronic sleep deprivation from intense research periods. Typically seen in a white lab coat over professional attire, she later adopts suits. Her behavior is defined by extreme logical reasoning and a notable lack of social awareness, famously manifesting as public undressing without hesitation. This habit stems from a researcher's mindset prioritizing practical solutions over social conventions, earning her the urban legend title "Stripping Woman." She justifies this with self-deprecating remarks about her body, revealing low self-esteem. Her career shifted when assigned to teach Child Errors despite her teaching license. Initially viewing the children as nuisances, she gradually formed strong bonds, especially with Edasaki Banri after caring for him during a rainstorm. This connection snapped when an experiment under Kihara's supervision plunged all her students into comas. Kihara prioritized data over treatment, prompting Kiyama's resignation. The experiment aimed to create an Ability Body Crystal. This tragedy became her driving force, dedicating her life to finding a cure for the children. After resigning, she joined the AIM Analytic Research Center as an AIM diffusion field specialist. Her attempts to revive the children involved 23 unsuccessful requests to use the Tree Diagram supercomputer. Inspired by the computational network potential shown by Misaka Mikoto's clones, she developed Level Upper—an audio file synchronizing listeners' brainwaves to create a networked consciousness pooling the calculation powers of roughly 10,000 espers. This network enabled the complex computations her research required. She distributed Level Upper as an urban legend promising esper level enhancement, fully anticipating it would induce comas in users. She concurrently developed a cure, demonstrating foresight despite the unethical method. Her technical approach utilized Kihara's brainwave tuning knowledge. During the Level Upper incident, Kiyama posed as a consultant aiding Judgment while secretly manipulating events. Shirai Kuroko, Uiharu Kazari, and Saten Ruiko uncovered her identity. Confronted, she kidnapped Uiharu to preserve network stability and used the collective esper abilities via Level Upper to become a Multi-Skill user, wielding diverse powers including teleportation, hydrokinesis, aerokinesis, cryokinesis, pyrokinesis, and energy projection. She clashed with Misaka Mikoto but was defeated. The network then manifested an AIM Burst entity, also destroyed by Mikoto. Kiyama was arrested. Following brief incarceration, she was released under Heaven Canceller's supervision; he shared her opposition to Kihara's methods and took custody of the comatose children. She investigated Poltergeist incidents—citywide disturbances caused by her students' subconscious AIM fields attempting to awaken. Her confrontation with Therestina Kihara Lifeline intensified upon discovering Therestina was Kihara Gensei's granddaughter, aiming to complete his experiment. Despite setbacks, including a trap by Therestina and an attack using the power-nullifying Capacity Down sound weapon, Kiyama persisted with aid from Mikoto, Uiharu, and Saten. In the climax, she overcame her trauma and used the Ability Body Crystal to successfully revive the children after receiving their symbolic trust. An emotional reunion followed where her students inquired about her eye bags, prompting a tearful response about her busyness. Her arc culminated in a hospital recovery scene, receiving a birthday gift—a blimp featuring her students' birthday messages—symbolizing reconciliation. Kiyama possesses no innate esper abilities but demonstrates exceptional expertise in neurology, AIM fields, and brainwave manipulation. Her strategic deception allowed her to operate undetected while assisting Level Upper investigations. During the network's activation, she temporarily wielded multiple borrowed powers classified as Multi-Skill. Her academic background implies high intelligence, having contributed to research on berserk abilities and level limiters under Kihara.