Lotta Otus is the younger sister of Jean Otus and serves as manager of the condominium Celebrity Mansion, where they both live. She oversees building operations and maintenance.

She possesses blond hair, usually in a ponytail, and blue eyes matching her brother's. Her typical outfit is a knee-length blue dress with gold buttons, layered over a white long-sleeved shirt featuring cuffs, a collar, and a red bow. She wears brown shoes and knee-high socks.

Practical and domestically competent, Lotta applies shrewdness to daily management. She excels at cooking and holds a noted fondness for wheat flour-based sweets. Her presence often symbolizes ordinary life and stability against political tensions.

Her background shifts significantly when Prince Schwan targets her in an assassination plot, aiming to eliminate her as a potential heir. During this kidnapping attempt, she discovers her royal lineage, learning that she and Jean are the rightful successors to the Dowa kingdom's monarchy, forcing her to confront this hidden heritage.

Despite this revelation, her core role and demeanor remain unchanged. She continues managing the condominium and supporting Jean, embodying normalcy. Her interactions, particularly through food and daily routines, act as grounding elements. The OVA "Regards" reinforces her enduring optimism as she faces future uncertainties while maintaining her lifestyle and relationships. Rail, a rookie ACCA officer from the Bādon branch, develops romantic feelings for her.