Marvel Frozen hails from a wealthy Texas family owning a large ranch near Dallas. Thrust into the parallel world of Byston Well, she initially serves as an Aura Battler pilot under the warlord Drake Luft. Recognizing Luft's ambitions for conquest, she defects early to join Nie Given's resistance, becoming a key figure opposing his forces.

While possessing initial romantic feelings for Nie Given, her emotional focus shifts toward protagonist Show Zama as their partnership deepens. Mutual affection develops, but wartime pressures largely prevent its expression. Marvel pilots multiple Aura Battlers, including the Dana O’shee, Fou, Bozune, and Botune, later inheriting the upgraded Dunbine after Show transitions to the Billbine. Her combat skills rival Show's, though her innate Aura Power—the energy source for piloting mecha—remains significantly lower than his near-limitless potential.

Beyond combat, she serves as the crew's emotional anchor aboard the Zelana ship, maintaining a stoic and level-headed demeanor that often mediates conflicts among resistance members. Her early encounter with Show proves pivotal; her revelations about Luft's tyranny catalyze his defection and alignment with the resistance.

When the conflict escalates to Upper Earth, Marvel reconciles with her parents in Texas and briefly travels to Hawaii with Show, highlighting her connection to her origins. During the final battle against Luft's forces, the Black Knight, Bern Bunnings, fatally stabs her during an assault on the enemy battleship Spriggan. Concealing her injury from Show to avoid distracting him, she remains in the Dunbine as it explodes, ensuring her sacrifice allows him to continue the fight.