Dete acts as Heidi's maternal aunt and primary guardian after the deaths of Heidi's parents. She raises Heidi from toddlerhood until the girl is five years old. Securing employment as a maid in Frankfurt forces Dete's hand; unable to take Heidi with her and believing her father bears responsibility, she relocates Heidi to her paternal grandfather, Alm-Onji, in the Swiss Alps near Dörfli. Though possessing some affection for Heidi, Dete consistently prioritizes practicality. Upon returning from Frankfurt and learning of an opportunity for Heidi to become a companion to Clara Sesemann, a wealthy wheelchair-bound girl, Dete first tries to convince Alm-Onji to let Heidi go. Failing this, she deceives Heidi into accompanying her under false pretenses. Heidi realizes the ruse during the journey, resisting vehemently with tears and screams on the train, but Dete insists relentlessly, taking her to Frankfurt against her will. At the Sesemann mansion, Dete deposits Heidi, formally transfers guardianship to the governess Miss Rottenmeier, and departs to pursue her own employment, effectively abandoning the child. Her subsequent role in the narrative is minimal. Her actions repeatedly favor perceived opportunities for advancement, often conflicting with Heidi's well-being or desires, driven by pragmatic concerns for financial stability and social positioning, coupled with a belief in the material advantages Frankfurt offers Heidi. She is 26 years old during these events. Across adaptations, her role remains consistent without significant evolution or redemption.