Hilda is a demon mercenary working mostly in her world's imperial capital. She displays distinct feline traits: cat-like, slit-pupil jade green eyes and pointed ears, usually hidden under a leather helmet. Her appearance is petite, featuring short auburn red hair and ears slightly darker than her hair. Her standard attire is a neutral-toned outfit with a high-collared sleeveless top revealing her midriff, silver armor over brown sleeveless gloves, fitted gunmetal trousers held by a belt with an ornate gold buckle, and brown boots under silver greaves. She also wears brown goggles with transparent lenses around her helmet.

Her notable abilities are exceptional night vision and acute hearing, letting her detect subtle sounds precisely. These senses earned her the mercenary nickname "Night Strider."

Little is known of her early life beyond her demon heritage. She built a career as a solo adventurer and mercenary, taking minor jobs like goblin extermination and escort duties. These offered limited pay due to her refusal to join larger parties needed for higher-paying contracts, partly to conceal her demon traits.

Her situation changed upon finding the interdimensional restaurant Nekoya. While clearing a goblin nest in a mine, she encountered its mysterious door, hoping for treasure. Inside, she met Aletta, a goat demon waitress who explained the restaurant operates only on the "Day of Satur." Intrigued, Hilda examined the menu and discovered soufflé cheesecake, a dessert incorporating cheese—a food for which she exhibits strong affinity, likely connected to her feline nature. Her immediate reaction was profound appreciation; she ate one serving and promptly ordered three more. This began her weekly tradition of visiting Nekoya solely for soufflé cheesecake on Saturdays.

Her behavior drew attention from fellow demon mercenaries Alicia (possessing bear-like strength) and Ranija (a reptilian humanoid from the Sand Nation). Suspicious of Hilda's frequent solitary trips and altered routine, they followed her to Nekoya. Inside, Hilda reluctantly introduced them. Alicia ordered baked cheesecake while Ranija chose the classic variant, both experiencing similar culinary revelations. This shared moment led Hilda to accept their proposal to form a permanent adventuring trio.

Later group visits revealed tensions over culinary preferences. During one encounter, the trio argued heatedly about the superiority of their cheesecake choices—Hilda favoring soufflé, Alicia baked, and Ranija classic. The disagreement escalated nearly to violence until Kuro, the restaurant's dragon guardian, intervened, confiscating their weapons and enforcing order under threat of expulsion. This set behavioral boundaries; arguments continued outside Nekoya, but no further conflicts occurred inside. The trio later sampled each other's preferred cheesecakes, showing evolving camaraderie despite differing tastes.

Her characterization includes distinct preferences. Beyond her primary obsession with soufflé cheesecake, she shows a broader fondness for cheese-based foods and displays a sweet tooth. She exhibits gourmet discernment, comparing Nekoya's offerings to imperial capital cuisine. Economic factors shape her choices; Nekoya's desserts fall within her budget, contrasting sharply with her world where sugar is a luxury typically accessible only to elites. She expressed astonishment at Nekoya's policy of unlimited complimentary sugar, particularly noting refined white sugar compared to the brown variety known in her realm. Her residence varies across adaptations, depicted as an outdoor basecamp in the manga and a riverside campsite in the anime.

Her developmental arc centers on social integration. Starting as an isolated operative concealing her identity, her Nekoya experiences facilitated meaningful connections with Alicia and Ranija. The restaurant served as neutral ground where shared culinary enjoyment overcame her reluctance toward collaboration, transforming her professional approach from solitary work to effective party-based adventuring while retaining her core preferences and personality.