Mie Daiwa is a minor yet recurring character in the anime Battle B-Daman: Fire Spirits. She is the foster mother of the main protagonist, Yamato Daiwa. Mie adopted Yamato when he was five years old, after he had been raised by cats for the early part of his childhood. She became his legal guardian and took on the responsibility of caring for him and overseeing his growth, including his development as a B-DaPlayer and his use of the legendary B-Daman known as Cobalt Blade. Mie is a young woman, aged twenty-two, who runs her own establishment in the town where she and Yamato live. Her restaurant is originally called Mie's Café, and it is later rebranded as Mie's Cat Cafe. Because she operates the café mostly on her own, she occasionally asks Yamato's friends and acquaintances, such as Liena and Armada, to help her with the work. This sometimes leads to conflict, particularly with Armada, who tends to dodge his chores. When Armada avoids his responsibilities, Mie can become noticeably frustrated, a reaction she believes is necessary to teach him accountability. Her personality is defined by a warm, loving, and often worried nature, especially concerning Yamato. She is a caring and protective mother figure who watches over him with concern, though she can also be assertive and firm when needed. Her motivations are rooted in her role as a guardian: she wants Yamato to be safe, happy, and to grow into a responsible person. She supports him in his B-Daman journey but is frequently anxious about the dangers he faces. Mie's role in the story is primarily that of a supportive family member. She provides a stable home base for Yamato and a source of emotional grounding. She does not participate in battles herself and has no notable B-Daman abilities or combat skills; her strengths are her nurturing nature and her determination to look after those she cares about. Her key relationships are centered on her son Yamato, whom she adopted and raised with genuine affection, and her interactions with his circle of friends, whom she treats with a maternal authority. Mie does not undergo significant character development over the course of the series, as she remains a steady maternal presence throughout. Her notable abilities are not related to B-Daman gameplay but to her management of her café and her skill in maintaining a household. She is characterized as a daring, hearty, and optimistic young mother with a dislike for indecisive people, traits that she has passed on to Yamato. Despite her sometimes airheaded nature, she is a devoted and reliable figure in his life.