Chiharu de Lucia is a pilot trainee in the Centezual class at Cadoques High's Aerial Division. She forges a close partnership with Mitsuo Fukuhara, piloting their aircraft while he serves as navigator. Affectionately calling him "Micchan" or "Mitty," she deeply respects his aviation knowledge and frequently relies on his expertise during missions. Chiharu readily engages in gossip, quickly grasping and spreading rumors among her peers.

Romantic undertones develop in her relationship with Mitsuo, with shared scenes indicating mutual affection. During a critical reconnaissance mission in episode 7, their aircraft encounters an advanced enemy fleet. Recognizing the threat to Isla, they selflessly fire flares to illuminate targets for allied bombers despite extreme danger. Mitsuo sustains grievous injuries, forces Chiharu to eject, then sacrifices himself and their plane as a decoy. Chiharu is left helpless in her parachute under enemy fire until instructors Juan Rodrigo Bandereas and Sonia Palez defy orders to rescue her.

Following Mitsuo's death, Chiharu battles severe psychological trauma, enduring prolonged depression, intense self-blame, and symptoms of post-traumatic stress. She becomes inconsolable, depicted in episodes overwhelmed by grief and haunted by battle flashbacks. These emotional struggles persist, affecting her interactions and daily functioning. After graduating, she undertakes a personal journey to deliver Mitsuo's posthumous medal of honor to his parents, seeking closure and fulfilling a final act of devotion.