Tōko Aozaki, a magus of the Aozaki lineage, excels in puppet-making and rune magecraft. Trained by her grandfather to inherit the family’s sorcerous legacy, her path fractured when her younger sister, Aoko, was unexpectedly chosen as the Fifth Magic’s successor. Enraged, Tōko slew their grandfather and fled to London’s Mage’s Association, severing ties with Aoko. Though their relationship later thawed, residual rivalry persisted—Tōko spitefully purchased items under Aoko’s name after losing her mystic eye-killing sunglasses.

At the Clock Tower, Tōko mastered runes and puppetcraft, reconstructing lost Primeval Runes to earn the prestigious Grand rank. Her research sought to recreate the original human form through dolls, a goal she abandoned upon concluding modern genetic diversity barred humanity from reaching the Root. Mentored by Inorai Valualeta Atroholm, she clashed with peers like Souren Araya and Cornelius Alba. Denied the title "Blue" in favor of Aoko, she adopted the moniker "Scarred Red" as a mark of defiance.

Her personality oscillates between calculated objectivity when wearing glasses and raw emotionality without them, blurring the line between her "true" self. A self-described romanticist, she pursues novelty with obsessive zeal, tinkering endlessly with curiosities. Her nomadic existence balances pragmatic ruthlessness with impulsive extravagance, frequently draining her finances.

Later abandoning her quest for the Root, Tōko shifted focus to mundane life and fleeting relationships. She bonded briefly with Mikiya Kokutō and Shiki Ryōgi while avoiding lasting ties. Notable exploits include trading two decades of her hair to acquire the werewolf Lugh Beowulf, collaborating on European supernatural cases, and waging a vengeful feud against the demon Francesca—killing her repeatedly until Aoko intervened.

In Lord El-Melloi II’s orbit, Tōko surfaces during the Rail Zeppelin incident and a Clock Tower reunion disrupted by her intrusion. There, she dismantled a magical illusion trapping attendees in a reconstructed past, demonstrating her mastery over intricate magecraft. Her interactions with El-Melloi II reveal a strategist adept at steering events to her benefit, leaving indelible marks on unfolding crises.

Tōko maintains the appearance of a woman in her late twenties through puppet bodies that "fix" her form. She dons orange accessories despite resenting the color’s link to her name and chain-smokes Dragon Smoke cigarettes, using their ash to inscribe runes. Her consciousness-transfer skill, honed through puppetcraft, has cheated death multiple times, ensuring her survival across lethal confrontations.