Before the manga and anime adaptations, Lux Arcadia's story began as a light novel. A deposed prince of the fallen Arcadia Empire, reduced to odd jobs at an all-female Drag-Knight academy, stumbles into the girls' bathing hall and ends up dueling the new kingdom's princess, Lisesharte Atismata. Branded the 'Undefeated Weakest' for refusing to fight back despite never losing, Lux enrolls as a student and is drawn into the rivalries surrounding Krulcifer Einfolk, Yoruka Kirihime, and the other pilots training alongside him. The source novel runs to twenty volumes, covering far more ground than either adaptation.