Tuuli, born in Ehrenfest, is the first surviving child of Gunther, a soldier, and Effa, a dye shop worker. Her younger sister Myne was born the following summer. Due to Myne's frequent sickness, Tuuli often cared for her while their parents worked, developing a strong sense of responsibility early on. This role was initially difficult as the pre-reincarnation Myne resented her and threw tantrums, but it solidified Tuuli's protective nature. After Myne's personality changed following Urano's reincarnation, Tuuli gained more independence while still supporting her sister.

Tuuli has blue eyes and naturally wavy blue-green hair, usually worn in a braid, though she wore it loose for formal occasions like her baptism. She closely resembles her mother, Effa, who is considered beautiful. By age twelve, Tuuli was tall and slender. Her appearance is notably cleaner than her peers due to Myne's insistence on frequent washing and shampoo. As her career advanced, she adopted more elegant manners and dress to suit her clientele.

Her personality is practical, caring, and responsible, often called an "angel" by Myne for her kindness and patience. Neighbors trusted her to supervise younger children during forest foraging from a young age. Despite her gentle nature, she experiences frustration with Myne's eccentricities and inner conflict as her professional success creates social distance from her lower-city origins. She deeply values family loyalty, insisting on concealing Myne's true origins from their younger brother Kamil. Tuuli harbors a dream of becoming a renowned seamstress like her idol, Corinna.

At age seven, Tuuli underwent her baptism, officially registering as an Ehrenfest citizen. Following societal norms where children often enter professions similar to their parents, she secured a seamstress apprenticeship through Effa's referral. She later joined the Gilberta Company as a *leherl* (apprentice), specializing in hair ornaments. Her exceptional lacework earned praise from high-ranking nobles, including Prince Anastasius, establishing her as one of Ehrenfest's most skilled artisans. Her apprenticeship taught her literacy and etiquette suited for high-society interactions, though she remained unprepared for formal business at the archduke's castle.

Tuuli's relationship with Myne is central to her development. She acts as a grounded counterpart to Myne's imaginative and obsessive tendencies, embodying maturity and community norms. She initially expressed concern over Myne's behavioral changes but accepted them out of relief for her improved health. Her protective instincts are evident when she shields Myne's secrets and well-being. Professionally, Tuuli admires Corinna, Benno's sister and a leading seamstress, aspiring to apprentice under her. However, her rising status creates emotional strain, as noted by Lutz and others, due to her growing detachment from their lower-city social circle.

Tuuli is one year older than Myne, though Myne's frailty and later two-year stasis in a *jureve* potion made the age difference appear more pronounced. The name "Tuuli" translates to "wind" in Finno-Permic languages.