Lynne Leinster is the second daughter of the Leinster family and the younger sister of Lydia Leinster. She is a student of the protagonist, Allen, and a supporting character in the story. Physically, she has short red hair and gray eyes, and she typically wears a school uniform. Despite her young age, Lynne is a prodigy with considerable natural talent, having inherited her sister’s abilities. Under Lydia’s guidance, she became skilled in both magic and swordsmanship, and she managed to achieve second place in the entrance exam for the Royal Academy. She has mastered the supreme fire spell Firebird, though her control over it remains imperfect.

Lynne’s personality is cheerful and energetic, with an earnest and straightforward demeanor. She deeply admires her older sister Lydia, and also holds a strong admiration for Allen, often addressing him as “Dear Brother.” This admiration fuels her desire to improve. At the same time, she harbors a competitive streak toward Tina Howard, viewing her as a rival. Her motivations are rooted in a wish to prove herself and to earn the approval of those she looks up to. Lynne plays a role as one of Allen’s students, interacting with the main cast primarily through her academic and magical pursuits. Her relationship with her sister Lydia is close and formative, as Lydia served as her mentor. With Allen, she is respectful and eager to learn, though her competitive nature sometimes emerges. Her dynamic with Tina is defined by friendly rivalry, as both strive to excel. Over the course of the story, Lynne continues to develop her skills and matures as a young noble, though her core traits of enthusiasm and loyalty remain constant.