Kiriko Aoi is the chief scientist and the commanding officer of the Dannar Base, the central headquarters for the battle against the Mimetic Beasts. She is a mature woman, typically depicted in her mid-thirties to early forties, and is the mother of the series' female lead, Anna Aoi. Kiriko is also the mother-in-law to the protagonist, Goh Saruwatari, and is married to the equally renowned robotics scientist Tatsuya Aoi.

In her professional capacity, Kiriko is a figure of authority who displays a cool and collected judgment, often overseeing the progress of the giant robots from the base's large control room. Her personality is a blend of a serious and harsh commander with an underlying, more playful and caring nature. As a boss, she demands discipline and is not afraid to make difficult decisions, such as ordering an electric shock to jolt her own daughter back to consciousness when she faints during a battle. Despite this stern exterior, she is capable of being fun and is a loving mother and friend, showing maternal tenderness especially toward her daughter and other young characters like Lou.

Kiriko's role in the story is primarily that of a mentor and overseer. She guides the younger pilots, including her son-in-law Goh, and manages the operations at Dannar Base. Her scientific expertise is crucial for understanding the mechanics of the super robots and the nature of their enemies, the Mimetic Beasts, who carry the Insania Virus. Later in the series, following the final battle against the Mimetic Beasts, she steps down from her command position to focus on research. Her goal becomes finding a cure for the Rabbit Syndrome, a condition that has caused Goh to become cocooned, demonstrating her dedication to her family's well-being.

Key relationships define much of her character. As a mother, she holds a complicated dynamic with Anna; she is both a demanding and unforgiving superior and a caring parent. With her husband, Tatsuya Aoi, she shares a partnership of equal scientific minds, although their relationship has had its disagreements, such as over his smoking when their daughter was young. She is aware of the affections of her subordinate, Kagemaru, but remains loyal to her husband. Despite becoming the mother-in-law to Goh Saruwatari, she does not hesitate to boss him around, treating him with the same no-nonsense attitude as any other pilot under her command.

Throughout the series, Kiriko shows subtle development. She transitions from a seemingly cold commander to revealing a more vulnerable and dedicated maternal side. Her character arc is highlighted by her devotion to saving her son-in-law, which requires her to give up her high-profile leadership role for quieter, more personal scientific work. Physically, her design is notable for its use of fan service, as her figure and clothing are often depicted in a comedic and exaggerated manner, such as her lab coat buttons popping open due to her chest.

Kiriko possesses a sharp intellect and is a brilliant scientist in the field of robotics, having co-created the very machines that protect humanity. She is also a chain smoker, frequently seen with a lit menthol cigarette, although it is revealed that she advocated for not smoking in the past. Her abilities are not physical combat skills but rather her strategic mind, leadership, and scientific knowledge, which are essential for coordinating the defense of Earth and developing solutions to technological and biological threats.