Mira Fermin debuted as a 16-year-old Vestal leading the Bakugan Battle Brawlers Resistance in New Vestroia, founded after Alpha Hydranoid’s tortured speech revealed Bakugan sentience. She co-created the group with Baron Leltoy and Ace Grit to free Bakugan from Prince Hydron’s Vexos. Her core drive was finding her missing brother Keith Fermin, who vanished during Hydranoid’s rebellion and reemerged as the masked antagonist Spectra Phantom. As a Subterra brawler, she commanded guardian Bakugan Magma Wilda and trap Bakugan Baliton. Her leadership rallied teammates during clashes and pushed allies like Baron to improve, though solo actions sometimes caused friction. She adapted tactics like flirtation or disguises to trick guards, notably during the Alpha City Dimension Controller sabotage mission. Discovering Spectra’s true identity as Keith led her to temporarily betray the Resistance; after losing a brawl to Spectra, she negotiated Vexos membership but deliberately sabotaged them by throwing matches. She reconciled with Keith when he abandoned the Spectra persona, and they fought together against King Zenoheld’s Alternative system, where their father Clay Fermin sacrificed himself to save Mira. Three years later in Mechtanium Surge, she transitioned from frontline combat to technical support. She obtained a new Subterra guardian, Roxtor, occasionally loaning it to allies like Marucho or Wynton. She engineered specialized Battle Suits such as Pyrus Doomtronic for Dan and Ventus Fortatron for Shun, collapsing from exhaustion during development and requiring hospitalization. Remote coordination included identifying Defendrix’s EM pulse to recover stolen suits and analyzing threats like Nonets or Mechtogan. Direct combat participation was minimal, limited to one brawl. She observed Dragonoid Destroyer’s energy depletion against Mechtavius Destroyer and aided evacuations as Bakugan City faced annihilation. Killed alongside Runo and Julie during Mechtavius Destroyer’s assault, her death was undone when the timeline altered via the Current of Time. Relationships included jealousy when Dan compared her to girlfriend Runo Misaki, though they maintained friendship; she occasionally showed romantic interest in Ace. Her bond with Keith endured, with epilogue scenes depicting their peaceful life post-conflict.