La Folia Rihavein, crown princess of the Aldegyr Kingdom, is the daughter of Lucas Rihavein and Polifonia Rihavein. Her royal lineage grants significant spiritual power, common among Aldegyr's royal women, making her blood a target for Magnus Craft's experiments. She is Kanon Kanase's niece through her grandfather's affair but regards Kanon as a true sister. Possessing distinctly European features, she is hailed as the Second Coming of Freya due to exceptional beauty. Her appearance features pale skin, hip-length silver hair with bangs primarily draped over her right face, and vivid sky-blue eyes. She typically wears a jacket-like trench coat over a white button-up shirt and black skirt, accessorized with a blue pendant gemstone on red ribbons and golden chains looped around her left shoulder. A medium-sized curse pistol with a bayonet-like knife attachment serves as her weapon, wielded with skilled marksmanship. For formal events, she dons elegant gowns like a strapless white design with gold accents and a tiara. Her personality blends regal poise with playful mischief. Cheerful, friendly, and observant, she quickly forms deep bonds, caring profoundly for allies like Kojou Akatsuki shortly after meeting him—even offering her blood when he was injured. Despite this amiable exterior, she is a hard realist with Machiavellian views, employing calculated manipulation to achieve goals. This includes toying with enemies and orchestrating mentally taxing scenarios to test allies' resolve. Her strong sense of responsibility aligns with her royal status, yet her methods reflect a willingness to use any means necessary. Key abilities stem from her high spiritual power and combat training. Using the Völundr System, she activates the Artificial Holy Sword by chanting: "Daughter of the gods that is within me... Protector of armies, age of the sword, bringer of victory and deliverer of death!" This transforms her temporarily into a spirit, manifesting the pseudo-holy sword through her bayonet. Enhanced agility enables significant aerial maneuvers during combat. Her genius intellect provides sharp insight and tactical wisdom beyond her years. The cursed firearm "Allard" is her primary weapon. Her involvement centers on aiding Kojou Akatsuki during major events. She became his third blood partner to awaken his third familiar, Al-Meissa Mercury, essential for rescuing Kanon from Magnus Craft. Later, she expressed interest in having Kojou's child, though he declined. As a foreign princess, her sporadic appearances are impactful, often resolving critical plot points. Royal duties occasionally intersect with conflicts on Itogami Island, where she leverages political influence and abilities. In the broader narrative, she is among those who marry Kojou in the future. Her background includes a privileged yet demanding upbringing preparing her for leadership and spiritual responsibilities. The royal bloodline's significance drives key conflicts as external forces seek its power. Character development reveals her increasing direct engagement in battles beyond diplomacy, showcasing combat prowess and strategic acumen during crises.