Mira Clay, also known as Mira Fermin, is a sixteen-year-old Vestal and the founder and original leader of the Bakugan Battle Brawlers Resistance during the events of Bakugan Battle Brawlers: New Vestroia. She is the daughter of Dr. Clay, a scientist who works for the Vexos, and the younger sister of Keith Fermin, who becomes the masked brawler Spectra Phantom. Before forming the Resistance, Mira initially viewed Bakugan as unintelligent tools, but her perspective changed when she witnessed Alpha Hydranoid being tortured and speaking out in vengeance. This moment made her realize that Bakugan were living creatures, and she resolved to free them from the Vestal invaders. She recruited Ace Grit and Baron Leltoy as the first members of the Resistance.

Mira's personality is characterized by a stubborn, tomboyish nature, though she can also display a more traditionally feminine side when the situation calls for it, such as pretending to be a crazed fan girl to distract guards or flirting to gain access to restricted areas. She is fiercely determined to find and reunite with her missing brother, a goal that often drives her to take risks and act independently. This intense focus on her brother sometimes puts her at odds with her teammates, especially Ace, with whom she frequently argues. Despite being the leader of the Resistance, she is not always fully trusted by others, in part because of her tendency to go off on her own. She is described by Baron as intense and is a warrior at heart.

As the story progresses, Mira's role expands. She welcomes Dan Kuso and his friends into the Resistance after they help defeat the Vexos Volt Luster and Lync Volan. She later leads missions to destroy the Dimension Controllers holding Bakugan captive. A major turning point occurs when she discovers that Spectra Phantom is actually her brother Keith. Overcome by the desire to be with him, she temporarily betrays the Resistance and joins the Vexos. However, she remains conflicted and eventually challenges Spectra to a battle with a wager: if she wins, she can return to her real brother; if she loses, she must serve him. She loses and is forced to become an enemy of the Resistance, but she later returns to the group after Spectra's own change of heart. Mira also battles alongside the other members against Prince Hydron and King Zenoheld, and she fights alongside her brother Keith on multiple occasions, including a battle against Mylene and Shadow Prove in Bakugan Interspace.

Key relationships shape her development. Her bond with her brother Keith is the strongest emotional drive; she idealizes him as her hero and desperately wants the kind-hearted Keith back from the ruthless Spectra persona. She also shares a close, sometimes teasing, friendship with Ace, who harbors romantic jealousy over her attention to Keith. With the other Resistance members and the Battle Brawlers, she acts as a decisive leader who pushes the team forward and encourages Baron to grow as a brawler. Later, when Dan proves to be the strongest brawler, she steps down as leader and defers to him.

In terms of abilities, Mira is a competent brawler who favors the Subterra attribute. Her primary partner Bakugan is Wilda, which evolves into Thunder Wilda and later Magma Wilda. She also uses the Bakugan Trap Baliton. She can hold her own against formidable opponents, having defeated Gus, Lync, and Mylene in various battles, and has also fought alongside Dan and Marucho in high-stakes battles. Despite her skills, she occasionally falls to superior opponents, such as when she lost attribute energy to Mylene and Lync. She continues to appear as a supporting character in the following season, Bakugan: Mechtanium Surge, where she returns with a new partner Bakugan, Roxtor.