Remilia Scarlet is known as the Scarlet Devil and is the mistress of the Scarlet Devil Mansion. It is rumored that she is a descendant of Vlad the Impaler.

Flandre Scarlet is the little sister of the Devil. She is both a vampire and a magical girl. While she looks up to her older sister Remilia, their full relationship is shrouded in mystery.

Vlad the Impaler was a ruler of Wallachia in Romania during the fifteenth century, and the inspiration for Count Dracula. He is called the Impaler because of his preferred method of execution―impaling people on stakes.

It is said that Remilia couldn't finish drinking her blood due to her small appetite and ended up spilling it onto her dress―staining it scarlet red. Apparently, those who saw this terrifying appearance named her the scarlet devil...

The whole Scarlet Devil Mansion came from the outside to Gensokyo. Remilia is the mansion's mistress, and while she may not look it, she is a vampire over five hundred years old. However, it is said that a wave of slight nausea is the worst you will suffer if she ever sucks your blood. Flandre, on the overhand, has only ever eaten food prepared by Sakuya and the fairy maids, so she doesn't know how to suck blood from a human. Apparently, there's a real risk that she will blow everything up and not leave a single drop behind...