Mylene Farrow emerges as a major antagonist in the series, the Aquos Brawler of the Vexos. Her cold, manipulative nature and pragmatic approach drive her to prioritize efficiency over emotional bonds, leading her to discard her original Guardian Bakugan, Elico, and Volt Luster’s Brontes once she deems their emotional connections weaknesses. Replacing them with the mechanical Macubass and Tripod Theta as her Bakugan Trap, she adheres to the belief that weapons with feelings hold no value. Blending cruelty with strategic calculation, Mylene habitually shifts blame to evade accountability, exemplified by her conspiracy with Prince Hydron to frame Spectra Phantom after the Dimension Controllers' destruction. Her ruthlessness surfaces in acts like taking Mira Fermin hostage during negotiations to access Phantom Data and attempting to detonate a Death Bomb during Bakugan Interspace’s collapse to eliminate adversaries. Despite her self-serving demeanor, she forms intricate dynamics within the Vexos: she mourns Volt Luster’s presumed death as a genuine friend, and though initially dismissive of Shadow Prove, she eventually acknowledges his loyalty. Their arc concludes with Shadow voluntarily joining her in a dimensional void, prompting her reluctant recognition of his devotion as they vanish hand-in-hand. Her allegiance to King Zenoheld remains pragmatically conflicted. Privately opposing his plan to annihilate Vestal and Earth via the Alternative Weapon System, she enforces it out of fear for her life. This contrasts sharply with her open contempt for Prince Hydron, whom she derides as a “spoiled brat” for operational incompetence, though she occasionally intervenes to spare him from Zenoheld’s retribution. Throughout the conflict, Mylene clashes repeatedly with the Resistance. Notable engagements include outmaneuvering Ace Grit by exploiting Elico’s attribute-altering capabilities and partnering with Shadow Prove in failed campaigns to secure Beta and Gamma Cities’ Dimension Controllers. Later infiltrating Earth to harvest attribute energies, she temporarily triumphs over Runo Misaki and Mira Fermin. Her final battle unfolds in Bakugan Interspace, where she and Shadow confront Spectra and Mira. Defeated, she spurns Spectra’s offer to defect and triggers a malfunctioning Death Bomb, destabilizing the dimension. As the portal engulfs them, Shadow’s voluntary leap into the void seals their ambiguous yet poignant connection. Mylene’s trajectory traces a gradual disillusionment with the Vexos’ cause, culminating in her operating as a “free agent” during the Alternative Weapon System crisis. However, her refusal to embrace collaboration or trust ensures her demise. Her legacy endures through a brawling record marked by tactical victories and critical defeats, cementing her role as a formidable yet fatally flawed adversary.