Marianne, whose full name is Marianne Orteus or Orteas, is the first princess of the Gilk Kingdom and the daughter of King Jilq and his former queen, who is believed to be deceased. She is the older half-sister of the protagonist Haruto, also known as Reinhardt, as well as of Laius, though she is completely unaware of this family connection. In her younger years, Marianne was overly confident and arrogant, once challenging Haruto to a duel only to suffer a decisive defeat. That loss became a turning point, humbling her and transforming her into a dedicated practitioner of self-improvement who is now known for her responsible, caring, graceful, and determined personality. She serves as the student council president at the capital’s magic academy, where she ranks first in magical combat and is recognized as an exceptionally powerful mage. Marianne plays a key role in bringing Haruto to the academy because she recognizes his immense potential, and she often tries to caution her brother Laius against his reckless behavior. After Laius was defeated by Haruto, his attitude improved, leading to a much better sibling relationship. Throughout the story, Marianne is motivated by a strong sense of duty to her family and kingdom, and she demonstrates a quiet interest in Haruto, whose abilities she deeply admires. Her development from a proud princess to a humble and capable leader is a defining aspect of her character.