Flandre Scarlet is the younger sister of Remilia Scarlet and the "dirty little secret" of Scarlet Devil Mansion, serving as the extra boss of The Embodiment of Scarlet Devil, the sixth entry of the Touhou Project series.
Because of her unstable personality and incredible destructive power, she lives in the basement of the mansion. She is immune to holy objects and has incredible physical strength; her sister has ordered her not to leave the mansion for nearly 500 years. She knows little about the world outside because of her leaving the mansion rarely, and, until the heroines arrived during the Extra Stage of Embodiment of Scarlet Devil, she has had no substantive contact with any humans other than Sakuya Izayoi.
She was voiced by Oma Ichimura in Touhou Azure Reflections and Misaki Watada in Touhou Spell Bubble.
Flandre has red eyes and short blonde hair, which is tied into a single ponytail on her left side. Wears a red skirt and vest, with a pink shirt underneath. Also wears a pink mob cap with a red ribbon attached. Her wings appear to be made of iron and prism shards. She carries a matching metal wand with her, which is apparently the mythical Lævateinn. Arranged from her back to the tip of her wings her 8 crystals are presented as follows: Light Blue, Blue, Purple, Pink, Orange, Yellow, Light Green and Light Blue again. Has longer hair than Remilia.