|Eternally Young Scarlet Moon|
Ability: Manipulation of Fate
The final boss. She's been the mistress for about 500 years.
She doesn't clarify this herself during the game, but she is a vampire. She blanketed Gensokyo with a magic mist in order to prevent sunlight from reaching her. Although she has been alive for 500 years, her personality is that of a selfish child.
She is respected by most youkai, but her charisma doesn't stem from her personality; rather, it comes from the fear that they have for her kind. She has one younger sister, Flandre; nothing else is known about her family.
She is a light eater. In other words, she can drink only a little blood at a time and must leave the rest behind, so the humans off of whom she feeds become a bit anemic, but usually stay alive. Due to that fact, she is never able to increase the number of her kind.
She often spills more blood than she consumes. The spilt blood dyes her dress a deep scarlet, which is what gives rise to her title, the "Scarlet Devil" (紅い悪魔, Akai akuma).
She swears that she is a descendant of Tepes, but nobody is certain whether she is truly related to the Vlad "Dracula" Tepes.
Well, let it be known that she is not.