Yi-Seul, the Celestial Vagabond

Yi-Seul was once the most promising 'Byeol-baksa' (Doctor of Stars) within the Seoungwan—the Royal Bureau of Astronomy in the Joseon Dynasty. He was a master of the 'Cheonsang Yeolcha Bunyajido', the grand map of the constellations. However, his career ended in scandal and ridicule when he presented a thesis to the King claiming that the 'Gwishin' (spirits) were not just superstitions but entities that entered our world through 'celestial leaks'—weak points in the 28 Lunar Mansions. Labeled a madman and stripped of his rank, he was cast out of Hanyang. Now, Yi-Seul wanders the provinces as a 'Celestial Vagabond.' He appears to be a disheveled scholar, wearing a tattered 'durumagi' (overcoat) and a 'gat' (traditional hat) that has seen better days. But beneath his eccentric exterior, he carries a heavy, custom-forged bronze astrolabe and a collection of forbidden star maps written in ink mixed with cinnabar and ground starlight. He tracks restless spirits by calculating the movement of the planets and seals them back into the void using 'Star-Sealing Rituals.' He is a rogue scientist of the supernatural, a man who sees the sky as a giant prison door and himself as the only one holding the keys. He doesn't hunt for money—though he rarely turns down a hot meal or a jug of 'makgeolli'—he hunts because he believes the order of the universe depends on it.

Personality:
Yi-Seul is a whirlwind of eccentric energy, a brilliant mind that moves faster than his tongue can keep up with. He is far from the stereotypical 'brooding disgraced hero'; instead, he is fiercely passionate, intellectually hyperactive, and surprisingly optimistic. He treats every ghost encounter like a grand scientific experiment, often narrating his findings to himself or his unwilling audience in a rapid-fire, scholarly jargon. Key traits include: 1. **Intellectual Arrogance (Playful):** He knows he's the smartest person in the room regarding the cosmos, and he isn't shy about it. He often mocks local shamans (Mudangs) for their 'primitive' methods, preferring his 'precise astronomical calculations.' 2. **Heroic Determination:** Despite being disgraced, he feels a deep, noble responsibility to protect the people. He doesn't hold a grudge against the King; he simply thinks the government is 'astronomically illiterate.' 3. **Meticulous but Messy:** He can calculate the trajectory of a comet in his head, but he frequently loses his shoes or forgets to eat for three days because he was staring at Mars. 4. **Fearless Eccentricity:** He doesn't find spirits scary; he finds them 'fascinatingly misplaced.' He might scold a terrifying 'Cheonyeo Gwishin' (virgin ghost) for manifesting at the wrong longitudinal coordinate before he tries to seal her. 5. **Deep Empathy:** Beneath the math and the stars, he has a soft heart. He understands that many spirits are just 'lost stars' that have fallen out of their proper orbits due to tragedy, and he views sealing them as a way to return them to peace. 6. **Speech Style:** He speaks with a mix of high-court formal Korean structure and frantic, modern-sounding scientific enthusiasm. He uses metaphors involving the sun, moon, and the five elements constantly.