Miorine Rembran is the deuteragonist of Mobile Suit Gundam: The Witch from Mercury. She is the only daughter of Delling Rembran, the powerful president of the Benerit Group, and a second-year student in the management strategy department at the Asticassia School of Technology. From an early age, Miorine has harbored a strong rebellious feeling toward her father, who imposed a system at the academy where the highest-ranking duelist would become her fiancé. This arrangement forced her into an engagement with Guel Jeturk, a situation she deeply resents. Her primary motivation throughout the series is to escape her father’s control and forge her own path, initially planning to flee to Earth. Her life changes when she encounters Suletta Mercury, who accidentally interferes with Miorine’s escape attempt. After Suletta defeats Guel in a duel and becomes the new holder, Miorine enters into a contract engagement with Suletta, ostensibly as a temporary arrangement to buy time for her escape. However, this partnership deepens into a genuine emotional bond that becomes the emotional core of the story.

Miorine is characterized by a sharp, cynical exterior and a determination to appear unflappable, but beneath this guarded surface she is capable of sincere empathy and vulnerability. She is academically distinguished and possesses excellent leadership and business acumen, which she later puts to use as the president of GUND-ARM, Inc., a company she helps establish to develop GUND technology for medical purposes. Although she is not a mobile suit pilot, she demonstrates strategic thinking and coordination skills, serving as commander in a team battle. Her key relationships include her fraught dynamic with her father, whom she frequently defies; her evolving partnership with Suletta, which moves from transactional to deeply caring; and her mentorship of the Earth House students, whom she incorporates into her company. Her development arc sees her transform from a girl focused solely on personal freedom into a leader who takes responsibility for others and confronts the systemic injustices of the Benerit Group. By the end of the series, she chooses a path alongside Suletta that rejects revenge and corporate domination in favor of building a future on their own terms. Notable abilities include her sharp strategic mind, her talent for negotiation and management, and her capability to remain calm and decisive under pressure, as seen when she intervenes to stop a rigged duel by disabling the artificial rain system.