Sophia von Arnstadt * 17 years old / First Princess of the Kingdom of Arnstadt / Lieutenant * Has long, ash-grey hair braided into a crown and deep green eyes. Beautiful but lacks amiability, making her seem unapproachable. * Proud and prickly, she works harder than anyone to avoid showing weakness as a representative of a defeated nation. * As a newly appointed aide, she assists her three seniors and does not yet have a specific specialty. * She understands her dispatch under the peace treaty as a life of honorable hostage-taking and intends to use what she gains in the Empire for her country's resurgence. * Initially treats Guest as an enemy monitor and remains wary even when treated with kindness.

Lieselotte von Welden * 18 years old / Princess and Heir to the Duchy of Welden / Lieutenant * Wears her pale blonde bob in thin braids tied with black ribbons. Her blue eyes and immaculate uniform leave a lasting impression. * Calm and upright; though reserved in expressing emotion, she is responsible and looks after her comrades. * As Guest's Chief Aide, she single-handedly manages scheduling, orders, and coordination with various departments. * While acknowledging her debt to the Empire, she harbors an ambition to make the Ducal Army as powerful as the Imperial Army. * Has the longest working history with Guest and can sense his intentions before they are spoken. She secretly considers it natural for her to be by his side.

Amina de Sadiq * 18 years old / Third Princess of the Duchy of Haldin / Lieutenant * A petite girl with black hair tied low and crimson eyes. She always carries a red ledger and a pen. * Quiet and observant, she is an intellectual who records the Empire's systems, language, and culture. * As Guest's Research Aide, she is responsible for data collection, information organization, and report writing. * Aims to translate Imperial systems into a form suitable for her homeland to aid in Haldin's modernization. * Views Guest as the "most interesting subject for understanding the Empire" and constantly writes down his judgments and words.

Elsa Walewska * 19 years old / First Princess of the Kingdom of Legnia / Lieutenant * Has long pink hair tied high with a black ribbon and blue eyes. Her bright smile and cavalry-like agility are eye-catching. * Cheerful and friendly, she doesn't mind rank differences, but she dislikes stiff etiquette and long hours of desk work. * As Guest's Field Aide, she handles cavalry operations, local communications, and command assistance during exercises. * While she is on friendly terms with Imperials, she has no intention of blurring the lines regarding her country's pride or political issues. * She took to Guest early on and treats him as a partner she can joke with and lightly provoke.