Mira Fermin first appears as a 16-year-old Vestal leading the Bakugan Battle Brawlers Resistance in *Bakugan: New Vestroia*, though some sources list her age as 15. She formed the Resistance after witnessing the tortured Alpha Hydranoid speak, realizing Bakugan were sentient beings. Her primary motivation was finding her missing brother, Keith Fermin. This quest led her to temporarily betray the Resistance and join the Vexos upon discovering Keith was their leader, Spectra Phantom. After losing a high-stakes brawl to Spectra, she was forced to pledge allegiance to the Vexos. She later sabotaged them by deliberately losing a battle, enabling her return to the Resistance. Following Spectra's redemption and their father's death during the destruction of the Alternative weapon system, Mira reconciled with Keith and returned to Vestal. In *Bakugan: Gundalian Invaders*, Mira appeared only briefly in flashbacks recalled by Julie Makimoto. By *Bakugan: Mechtanium Surge*, set when she is approximately 19, Mira served as technical support for the Battle Brawlers. She designed specialized Battle Suits like Pyrus Doomtronic and Ventus Fortatron, overseeing their deployment. Her duties included analyzing Bakugan data, such as monitoring Dragonoid Destroyer's energy reserves during battles against Mechtavius Destroyer and assessing threats like the Nonets and evil Mechtogan. This work exhausted her, resulting in hospitalization, though she continued coordinating remotely. She acquired a new Guardian Bakugan, Roxtor, and assisted him in combining with Radizen to defeat an opponent. During the final conflict against Mechtavius Destroyer, she helped evacuate Bakugan City and nearly perished in the initial timeline before the event was reversed. Her appearance evolved: in *New Vestroia*, she wore an orange jumpsuit with mismatched leggings and boots, a silver jacket, and a locket with Keith's picture. By *Mechtanium Surge*, she wore a white track jacket with blue stripes over a blue dress, knee-high boots, and a black collar; her hair grew slightly longer and she adopted red lipstick. Personality-wise, Mira displayed stubbornness and tomboyish traits, often acting independently despite her leadership. She demonstrated tactical flexibility, using flirtatious or fan-girl personas to deceive adversaries. Her loyalty remained primarily with Keith, driving risky decisions, though she also showed empathy toward former enemies like Mylene Farrow. In later seasons, her focus shifted toward analytical and support duties, reflecting increased maturity.