Jessica Orin is a formidable esper student honed at Lady Kahn's institution under Cornelia Prim's tutelage. Suppressed traumatic memories form her core, specifically manipulated recollections falsely implicating Locke in her parents' murder and her childhood scarring. This psychological conditioning molds her into a dedicated weapon against Locke, driven by vengeance. Her unique power to nullify other espers' abilities earns her the formidable designation "Esper Killer," rendering her invaluable to Lady Kahn's schemes.

As part of Kahn's strategy to infiltrate the Galactic Federation, Jessica undergoes memory alteration, adopting the carefully constructed identity "Amelia." Embedded within the Federation, this persona encounters and forms a romantic relationship with Colonel Ryu Yamaki, a key operative linked to Locke. This unexpected emotional entanglement complicates her mission, temporarily eclipsing her programmed vendetta.

Her suppressed memories violently resurface during a confrontation with Locke, shattering the Amelia persona and reigniting her original identity and mission. This resurgence fuels intense hostility, triggering aggressive confrontations where she unleashes her power-negating abilities against him. Her path reaches a critical juncture when the truth behind her fabricated trauma—exposing Lady Kahn's direct role—is revealed. This revelation forces a profound reevaluation of her allegiance and motives, culminating in her decisive rejection of Kahn's influence.

This turning point shifts Jessica from antagonist to Locke's ally. She consciously aligns herself with him to dismantle Kahn's grand design for an esper-ruled "Millennium Kingdom." Her development concludes as she abandons the path of vengeance, rejecting her conditioning and forging a self-determined future free from Kahn's manipulation.