If the scarlet mist expands into the shrine and begins seeping into the outer world, then upset humans from the outer world are going to want to destroy Gensokyo. As a shrine maiden of the Hakurei Shrine, it's her duty to restore the good weather that the mist is blotting out. Oh, and defend the shrine and the world it protects.
The boss of Stage 1, youkai of darkness Rumia interrupts you during your search of the source of the scarlet mist. With her around, there's not enough light to find the way to the lake, so you might as well put an end to her nighttime snack craving. Rumia's attacks are not very sophisticated, and she chooses her normal attacks randomly.
The midboss of Stage 2, this powerful fairy greets you with a circular spread of kunai and aimed shots of ice. She's not very strong though, and has no spell card. After defeating Daiyousei, you're accosted by her friend...
The boss of Stage 2, Cirno has finally found a interesting thing to play with, and wants to show you who's the boss of this lake. You'll never find the culprit with this obstruction around, so why not brave a hailstorm or two? Her specialty is ice and freezing magic, so she's someone who'd be pretty useful on a hot summer day.
The boss of Stage 3, Meiling is the outer door guard of the Scarlet Devil Mansion, and does her job with flair. Wielding rainbow magic and an interesting dash, she stands between you and the center of the mist. But one wonders; what is a Chinese girl doing here anyway? Perhaps she's no ordinary human.
The midboss of Stage 4, this young demon comes across you as you venture into the library. She attacks with large globe shots and other scattered small shots, but she's really not that tough. Evade the first wave, and you'll be through in no time.
The boss of Stage 4, Patchouli is the librarian of the mansion. As the guardian of the books in the library, she stops you as you try to find the cause of all this mist. She may be weak in body, but her magic is top-notch. She often attacks with lasers and elemental spells; few can survive her deadly barrage.
Wandering about the great halls of the mansion, you encounter the mysterious chief maid Sakuya Izayoi. She looks like a normal human, but don't be fooled: with her astonishing ability to control time and her remarkable skill with knives, she truly is a dangerous opponent. Many of Sakuya's attacks involve freezing time and redirecting her knives in mid-air; take this time to plan your escape!
The master of the house, vampire Remilia Scarlet is the cause of all the scarlet mist that has been hanging around Gensokyo. Although she appears young, she is in fact over 500 years of age, and claims to be a descendant of Tepes himself. As such, Remilia is a difficult opponent. Her attacks are varied and deadly; be prepared if you are to confront her, lest you find yourself an unwilling inhabitant of a scarlet Gensokyo...
Flandre is Remilia's younger sister and the extra stage boss. Having lived, alone, in a basement for 495 years, the commotion of recent events drew her attention. Flandre is only 5 years younger than her sister, but possesses far greater power; all alone, deep underground, it's hard to say that this is a blessing rather than a curse. Flandre attacks with incredibly destructive magic: tread carefully, if you want to survive the frustrations of five centuries!