Oriana Thomson emerged from an English devout Christian family, beginning her path as a Roman Catholic nun committed to humanitarian work. A pivotal fracture in her faith occurred when she assisted Emily Laughton onto a bus later destroyed in a terrorist attack; this event catalyzed her departure from the Church and eventual turn to magic.

She forged a new identity as a mercenary and magic courier, earning the moniker "Route Disturb" for unparalleled evasion and escape tactics. Her methods strategically leveraged collateral damage—destroying bridges or igniting fires—to thwart pursuers. This evasion expertise inversely honed her tracking skills, enabling her to anticipate pursuers' methods. She deliberately avoided reusing spells, enhancing her unpredictability.

During the Daihasei Festival, Oriana served as a field agent for the Roman Orthodox Church under Lidvia Lorenzetti. Her mission involved deploying the Croce di Pietro artifact within Academy City to manipulate its populace. Her "Silent Coin" spell initially concealed her presence, but physical contact with Touma Kamijou disrupted it. Subsequent chases led to accidental injuries inflicted via traps on bystanders Aisa Himegami and Seiri Fukiyose, actions she later expressed regret over. Defeat by Touma Kamijou and Stiyl Magnus in District 23 halted the artifact's activation.

Imprisoned afterward by the English Puritan Church, Oriana negotiated her release to join Necessarius and the Anglican Church. Seeking redemption, she aimed to protect civilians amidst rising tensions between Academy City and the Roman Orthodox Church. This shift aligned with her stated goal of achieving world peace through clear moral binaries, irrespective of organizational loyalties.

In the British Royal Family Arc, partnered with Touma Kamijou under Anglican employ to pursue the magical terrorist group New Light, she analyzed their movements using London's surveillance blind spots. She deployed crowd-clearing fields to minimize civilian harm and engaged Lessar in combat. Her tactics included intercepting the magical artifact "Steel Glove" and advising Touma on evacuation routes during the Knights of England's assault, though external attacks ultimately separated them.

Oriana wielded "Shorthand" magic—improvised, disposable grimoires scribbled on flashcards. These combined incompatible elemental symbols (fire, water, earth, wind) and colors to generate unique spells, each self-destructing after use and lasting seconds to an hour. Notable spells included "Blade Crater" (vacuum blades), "Drop Rest" (non-lethal knockout), and communication or counter spells exploiting astrological angles. Her combat style integrated physical seduction techniques to distract opponents, though prolonged battles strained her endurance.

Physically, Oriana presented as a tall blonde with blue eyes, often obscuring her right eye with her hair. She initially wore revealing gray work clothes, later adopting a gypsy skirt and chest wrap. Her figure frequently drew attention, which she exploited for tactical advantages.

Her character evolved from a minor antagonist motivated by contractual loyalty to a cooperative force prioritizing civilian protection, consistent with her core desire to eliminate ambiguity in achieving peace.