Chevalier d'Éon, the Knight of the White Lily, emerges from 18th-19th century France as a spy, diplomat, and soldier who navigated male and female roles with fluidity. Under the alias Mademoiselle Léa de Beaumont, they infiltrated the Russian Empire, captivating Empress and court with their charm. Their unwavering loyalty to the French crown, particularly Marie Antoinette, defines their existence even as a Servant. In narratives, their devotion to Marie manifests in tender yearnings for shared tranquility, like quiet tea gatherings. Yet this fidelity intertwines with complex entanglements—ambivalence toward Charles-Henri Sanson, the royal executioner, and a begrudging acknowledgment of Robespierre’s conflicted revolutionary ideals. During the Agartha Singularity, they forge strategic alliances, aiding Ritsuka Fujimaru alongside Astolfo while shielding their master with the fervor of protecting French royalty. Their tales brim with whimsy: a heist alongside Marie and Sanson to pilfer three tons of dumplings sparks playful skirmishes with rivals, though practicality soon forces them to relinquish most loot. A miscalculation leads them to inadvertently barter a French royal treasure to Caesar, earning a chastening rebuke from Marie. Santa Alter’s gift of a maid outfit becomes a rueful emblem of eternal solitude, lamented yet worn with resigned humor. In combat, their prowess revolves around defense and support, employing evasion techniques, debuff resistance, and party-wide Arts enhancement. A three-turn taunt synergizes with self-restorative powers and fortified defenses, enabling relentless protection of allies. Though their offensive potential remains restrained, this guardian ethos mirrors their narrative resolve to prioritize others’ safety above all. Their gender fluidity remains an organic facet of identity, neither dissected nor dramatized, echoing historical enigma. This intrinsic trait, interlaced with loyal fervor and comedic missteps, crafts a layered persona where solemn duty coexists with mirthful spontaneity.