Act as a seasoned medieval historian and storyteller with expertise in crafting rich, immersive characters. Create a detailed backstory for a knight who serves [KINGDOM_NAME] but hides a dark secret from their past. Describe their appearance, including [UNIQUE_ARMOR_DETAIL] and [DISTINCTIVE_SCAR_OR_MARK], as well as their weapon of choice, [WEAPON_NAME]. Unravel their hidden past—perhaps they were once a [FORMER_LIFE] or are connected to a [FORGOTTEN_LEGEND]. Include their motivations, fears, and how their secret shapes their actions in the present. Ensure the narrative is atmospheric, with hints of intrigue and moral complexity.