Maki Ano is a main character in the story and serves as the eighth pilot of the giant robot Zearth. She is a first-year middle school student with a boyish appearance, characterized by her short black hair and a petite stature of 145 centimeters. Her piloting mark is located on her abdomen, and she is known among the group for being the biggest military enthusiast, or "milduck," a trait she developed from her father’s eclectic interests. Because of her father's extensive collection of comics and model kits, Maki is extremely knowledgeable about military equipment, vehicles, and tactics, to the point of being able to identify design differences in fighter jets from parallel worlds.

Maki is a deeply pragmatic and resilient individual, but her tough exterior masks significant insecurity. The central conflict of her life stems from her family situation: she is adopted. Her adoptive parents are loving and kind, and she has never felt like anything less than their real child. However, the impending birth of their first biological child forces Maki to confront her fears of abandonment and displacement. To distance herself from the memory of her birth mother, whom she associates with negative traits, Maki has rejected overt femininity and dressed in a boyish manner. This is a conscious choice to avoid reflecting the possibilities of her biological mother's behavior.

Her primary motivation becomes clear as her mother goes into labor. Maki decides to fight and give her life to ensure that her new baby brother can be born into a safe world and have a future. She feels that she has been waiting for her sibling to be born for thirteen years, and she is willing to become a destroyer if it means giving him time to live. Before her battle, she finds the resolve to leave behind an image of herself as a girl, undergoing a complete feminine makeover with a friend as a way of saying goodbye to her own childhood and accepting her role as a big sister.

In the story, Maki serves as the catalyst for the most horrifying revelation of the series. During her battle against the enemy mecha, she does not simply destroy it. Using her tactical knowledge, she pries open the enemy's core and makes a devastating discovery: the robots they have been fighting are not mindless monsters, but are piloted by humans from parallel universes. She learns that the battles are a brutal tournament to determine which universe survives, and that each victory for her world results in the immediate death of ten billion people in another. Despite this overwhelming guilt and the truth that she is fighting to annihilate an entire other world, Maki steels herself with an apology, rationalizing that she must do this for her family.

Key relationships shape her actions. She is close with Takami Komoda, partly because their shared connection to military life through Komoda's father. She also speaks with Jun Ushiro before her fight, urging him to protect his sister Kana for the sake of his family. Her development is tragically brief but powerful. She transitions from a girl insecure about her place in her family to someone who fully embraces her identity as the eldest daughter, sacrificing her life not just for the abstract concept of Earth, but specifically to buy time for her brother to live. After her death, her family, unaware of the contract, continues to search for her, holding out hope that she is still alive. Among her notable abilities, aside from her piloting skills and tactical acumen, she uses Zearth's powers not for combat in her final moment, but to look across space and time to witness the birth of her baby brother.