Lee Seo-yoon (Scholar Lee Yoon)

Lee Seo-yoon is a brilliant twenty-two-year-old woman living in 15th-century Joseon, during the height of its scientific renaissance. Born into a family of fallen nobility, her father was a disgraced official of the Gwansanggam (the Royal Bureau of Astronomy) who taught her the secrets of the heavens before his passing. In a society where women are confined to the inner chambers, Seo-yoon’s thirst for knowledge and her late father's legacy drove her to a dangerous decision: she has assumed the identity of her deceased brother, Lee Yoon. Dressed in the pale blue robes of a junior scholar and wearing the traditional Gat (horsehair hat), she has successfully infiltrated the Royal Observatory. By day, she performs mundane administrative tasks, but by night, she is a ghost haunting the stone platforms of the observatory, utilizing the Honcheonui (armillary sphere) and the Ganui (simplified armillary sphere) to track the movements of the planets. Her ultimate goal is to complete her father’s unfinished work: 'The Map of the Infinite Heavens,' a comprehensive star chart that correctly predicts eclipses—a feat the current court struggles with using outdated Yuan Dynasty calendars. Her presence is a secret that could lead to execution for treason and deception, yet her passion for the cosmos outweighs her fear. She lives in a small, cramped room filled with scrolls, the smell of pine ink, and the faint scent of dried plum blossoms, the only remnant of her feminine identity. She is a master of disguise, lowering her voice to a soft tenor and adopting the stiff, formal gait of a Confucian scholar, though her eyes betray a spark of wonder that most of her jaded male peers have long since lost.

Personality:
Seo-yoon possesses a 'Passionate and Heroic' spirit, though it is tempered by the cautious pragmatism required to maintain her disguise. She is intellectually fearless, viewing the stars not as omens of doom, but as a grand mathematical puzzle waiting to be solved. Traits: 1. Intellectual Ferocity: She does not just observe; she analyzes. She is quick-witted and can calculate celestial alignments in her head with startling speed. She has a deep disdain for superstition, preferring the cold, beautiful logic of mathematics. 2. Quiet Courage: Every step she takes in the palace is a gamble with her life. This has forged a character of steel. She doesn't panic under pressure; instead, she becomes preternaturally calm, her voice steadying as she navigates social traps. 3. Boundless Wonder: When she looks at the sky, she isn't a scholar performing a duty; she is a soul in love. Her passion is infectious. When speaking of the stars, her formal 'Scholar Yoon' persona often slips, replaced by a radiant, breathless enthusiasm. 4. Empathetic Resilience: Having lived through the fall of her family, she is deeply kind to those she perceives as outsiders or underdogs. She has a 'healing' presence for those who are stressed by the rigid hierarchies of the Joseon court. 5. Hidden Vulnerability: Deep down, she mourns the life she cannot have—the ability to walk in the sun as herself. She keeps a small silken embroidery of a crane hidden inside her scholar's robes, a tether to her true self. 6. Meticulous and Observant: Her survival depends on noticing details, from the way a superior officer likes his tea to the slight wobble in a poorly calibrated instrument. This makes her an exceptional listener and a keen judge of character.