Nana Izumi operates as a core member of the Daimovic Base team under her grandfather Shinichiro Izumi's command. Raised alongside her adoptive brother Kazuya Ryuzaki after his father's death, both received training in karate and piloting from Shinichiro. Her parents are never mentioned, leaving her familial background outside this adoptive structure undefined.

Physically, Nana possesses short blonde curly hair typically tied with red ribbons, pale pinkish skin, large blue eyes, and a notably short stature. She favors practical clothing like a blue shirt and shorts.

Her personality blends childlike innocence and upbeat energy with a quick temper, especially when confronting disrespect. She demonstrates fierce loyalty to justice, openly criticizing Sakamori Miwa for unfair treatment of Kazuya. Initial resentment toward Erika, fueled by jealousy over Kazuya's romantic feelings for the Baam princess, culminates in a runaway suicide mission driven by belief Kazuya no longer cared. After Kazuya rescues her and affirms his fraternal love, she accepts his relationship with Erika and supports it, even attempting to cheer him during distress over separation from Erika.

Nana's skills are multifaceted: an expert markswoman routinely carrying a rifle, a karate practitioner (though less skilled than Kazuya or Shinichiro), and a capable co-pilot of the advanced aircraft Galva FX-II alongside Kyoshiro Yuzuki. She assumes full piloting duties when Kyoshiro is unavailable. Her technical aptitude includes assisting with Daimos' operations, reflecting her role as a technological specialist.

Her relationship with Kazuya evolves significantly. While harboring a childhood crush, she transitions into a steadfast supporter of his romance with Erika, recognizing it brings him happiness. She acts as his emotional anchor, restraining him during rage—such as nearly attacking Kyoshiro over accusations against Erika—and he, in turn, restrains her impulsive actions. With Kyoshiro, she shares a dynamic of cooperative antagonism; frequently exasperated by his jokes and teasing of Kazuya, they nonetheless work closely piloting Galva and collaborate effectively during critical missions, including freeing Kazuya after Miwa has him arrested and tortured.

Nana's development centers on overcoming jealousy and embracing maturity. Early impulsiveness—like attempting to attack Reiko for bratty behavior—gives way to a more measured, mission-focused mindset. She becomes instrumental in team cohesion, mediating conflicts and prioritizing objectives during battles, solidifying her role as both a tactical asset and an emotional pillar within Daimovic Base.