Izumi Moriyama functions as an assistant in ZAT, uniquely positioned as the team's sole official female member. Her duties include liaison coordination and data analysis at headquarters, supplemented by active frontline mission participation when necessary. She maintains composure in crises, matching male colleagues in driving proficiency, marksmanship, and rapid response. On duty, she attentively prepares refreshments such as tea, ice cream, and chewing gum for teammates. Privately, her personality emerges as lively, bright, and witty, with a noted fondness for fairy tales. She develops romantic feelings for Kotaro, explicitly expressing a Christmas wish to marry him. During a mission safeguarding a girl named Megumi, Megumi attempts to coerce her into killing Hertz; after refusal, Moriyama is rendered unconscious and subjected to mind control. Ultraman Taro—Kotaro transformed—intervenes to rescue her. In the series finale, she stands among ZAT members bidding Kotaro farewell. A distinct character named Izumi features in the Netflix anime adaptation. She partners with Kotaro Higashi, a journalist investigating mass disappearances in New York. Captured by the responsible aliens, she is vaporized by an energy beam during confinement. This fatality triggers Kotaro’s uncontrolled empowerment following identical beam exposure, leading him to become Ultraman Taro via an experimental suit supplied by the fighter Jack. Her role primarily catalyzes Kotaro’s transformation into a hero.