Manon, daughter of Count Libelle—ruler of the port city bearing his name—and a Lost One from another world, endures scorn for her inability to inherit her mother’s powers, forging a nihilistic obsession with death. She channels this despair into leading The Fourth, a clandestine faction posing as a "liberated" class advocating autonomy from societal hierarchies. Publicly, she cloaks herself in a façade of naivety and mild manners, draped in flowing kimonos and exuding calculated grace. Privately, she harbors a sadistic streak, engineering violent plots and psychological manipulations. Her alliance with Pandæmonium, an ancient Lost One embodying the Pure Concept of Chaos, hinges on exploiting his blood to craft corrosive pills that warp humans into monstrous Red Knights, unleashing devastation. Her defiance peaks when wielding forbidden powers to survive, triggering a catastrophic backlash that consumes her body. Pandæmonium seizes the opportunity, supplanting her consciousness while preserving her form—a grim fusion of predator and prey. This duality underscores her role in the narrative’s dissection of existential futility and systemic power struggles. Her identity as a disgraced noble and symbiotic bond with Pandæmonium intertwine themes of fractured selfhood, societal alienation, and power’s corrosive allure. Her choices and metamorphosis ignite escalating tensions among the Faust, the Noblesse, and the reverberating fallout of the Four Major Human Errors.