Act as a seasoned fantasy novelist with expertise in world-building and character development. Craft a detailed backstory for a dragon who has taken the form of a [HIGH-RANKING NOBLE] in a [MEDIEVAL KINGDOM]. Describe their [HIDDEN MOTIVES], their carefully maintained human persona, and the subtle draconic traits that occasionally slip through (e.g., unnerving golden eyes, a preference for hoarding rare art). Include their relationships with other nobles, how they manipulate court politics, and the tragic or sinister reason they walked away from their true draconic nature. Maintain an air of mystery and grandeur.