Aya Kouda, a spirited 10-year-old with short red hair styled in a bob and blue-grey eyes, adorns her hair with pins on both sides. Her wardrobe features a tan duffle coat fastened off-center, a bright yellow pleated dress, violet tights, and pink shoes. Hailing from Osaka, her speech carries the distinct cadence of the Kansai dialect. Raised in a household shadowed by loss—her mother and sister perished early—Aya endures the strict upbringing of a father who enforces relentless karate training, deeming her a "failure of a woman" while relentlessly comparing her to the deceased. Yet she clings to his idealized sense of justice, molding herself into a self-declared "warrior of justice." Bold and stubborn, Aya confronts peril headlong, whether dismantling a train station bomb or unraveling a global vampire conspiracy masterminded by Ōchi Fukuchi. Though lacking supernatural prowess, her sharp intellect and courage let her navigate crises, deducing truths others overlook. Fleeing Fukuchi after photographing his crimes during the Tenjin Gosui arc, she hides inside a coffin containing Bram Stoker, an ancient vampire. Dubbing him "Bram-chan," she coaxes his aid against Fukuchi, awakening his dormant empathy by reminding him of his lost daughter. In a pivotal act, she leverages a desk and her own weight to extract the holy sword sealing Bram’s power, reigniting his abilities to reverse the vampiric plague. Her tenacity transforms her from a neglected child into a linchpin of conflict resolution. She challenges Doppo Kunikida’s rigid principles yet earns his respect, while her bond with Bram evolves into a pact of mutual protection. Her father’s harsh legacy remains a driving force, intertwining her thirst for justice with the scars of familial strife. Inspired by author Aya Kōda’s explorations of family and society, her fictional counterpart mirrors these themes through resilience and layered relationships, cementing her role as both a product of tragedy and an architect of hope.