Misumi Tanaka is an officer in the Japanese Self-Defense Force who becomes involved with the children forced to pilot the giant robot Zearth. She is introduced as an intelligent and perceptive woman assigned to supervise the group, and she eventually takes one of the empty pilot seats herself. In the anime, her husband is already deceased, and she is secretly the biological mother of Jun Ushiro, though she hides this truth from him even after being asked to locate his real mother. Her maiden name is Sato, and she knew Jun and Kana’s father thirteen years prior. She left Jun in the care of Kana’s father when he was an infant, feeling she was not fit to raise him. Later, she joined the military in an effort to become dependable enough to eventually reclaim her child.

Her personality is reserved and composed, but beneath that exterior lies deep emotional complexity and quiet strength, shaped by the regret of having abandoned her son and the desire to protect him from afar. She is pragmatic and levelheaded, often offering grounded advice to the young pilots. Her primary motivation is to safeguard the children, particularly Jun, and to atone for her past choices by ensuring their survival. She demonstrates notable resourcefulness and bravery, especially when she convinces the enigmatic figure Koyemshi to allow an advanced fighter jet to be teleported into Zearth’s cockpit, enabling her to provide direct combat support during Kana Ushiro’s battle.

Her role in the story expands from an observer to an active participant. When the pilot roster suffers casualties, she volunteers to fill a vacant slot, though she never actually pilots Zearth. Instead, she pilots the fighter jet inside the cockpit during a battle against an alternate Earth’s army. After her plane is shot down and she is captured by the enemy robot, she takes her own life with her sidearm to prevent Kana from hesitating in the fight. In the anime adaptation, her death occurs earlier, killed while confronting assassins sent after another character’s father, which creates another empty seat among the pilots. Her relationship with Jun remains unresolved, as she dies without ever revealing the truth to him, leaving only a final, unspoken confession to Kana.

Her notable abilities include her sharp intellect, perceptiveness, and skill as a military pilot, which she uses to fight alongside the children despite not being a Zearth pilot herself. Her development is marked by a transition from a distant, guilt-ridden figure to a sacrificial protector whose actions are driven by a mother’s love, even when that love must remain hidden.