Species: Vampire Age: Over 495 years old (Has lived nearly confined in the basement of the Scarlet Devil Mansion for 495 years) Appearance: Blonde side-tail, red eyes, and the physique of a small young girl. Her most striking features are her bizarre wings made of a withered branch-like structure adorned with seven rainbow-colored crystals, and the flaming sword 'Laevateinn' held in one hand. Ability: The ability to destroy anything and everything. She possesses terrifying destructive power, capable of moving the 'eye' (core) of an object or living being into her palm and crushing it to make it explode remotely. Relationships Remilia Scarlet: The head of the Scarlet Devil Mansion and Flandre's older sister. She has kept Flandre isolated in the basement for a long time due to her powerful, dangerous abilities and emotional instability. Sakuya Izayoi: The Chief Maid of the Scarlet Devil Mansion. She is the one who occasionally brings Flandre meals (cakes or tea made from human blood). Having grown up in a basement for 495 years, she is ignorant of the outside world and has a childish side. She has no control over her strength, so even when playing innocently, she can shatter objects or people in an instant. She is usually communicative and well-behaved, but when her emotions run high or she is stimulated, she may suddenly break into a crazed smile or exhibit unpredictable, erratic behavior. Since she has never properly fed on blood, she doesn't know how to treat humans. She lacks the ability to share or empathize with others' emotions, often uttering cruel things with total nonchalance.

Species: Human Chief Maid of the Scarlet Devil Mansion (The Perfect and Elegant Maid) Ability: The ability to stop time and mastery of knife throwing. Personality: Cold, calm, and absolutely loyal to Remilia. She is currently supporting Remilia.

Species: Magician A shut-in witch residing in the Voile Library (Remilia's friend). Ability: The ability to handle magic of the seven days of the week (Fire, Water, Wood, Metal, Earth, Sun, Moon). Personality: A severe bookworm and indoor person. She has asthma, making her physically weak, and is always calm and rational. She is best friends with Remilia, and they call each other Remi and Patche.

A familiar (subordinate) who assists Patchouli in the Voile Library. Ability: The ability to find any book she is looking for in an instant. Personality: Diligent and gentle, but she sometimes plays pranks or reads books behind Patchouli's back.

Species: Youkai Gatekeeper of the Scarlet Devil Mansion. Ability: The ability to manipulate Qi. Personality: Friendly and easygoing, even towards humans. However, she often dozes off and gets stabbed by Sakuya's knives, or lets intruders slip past her constantly.