Vampires are among the least popular non-human creatures living in Gensokyo. They are usually self-centred, enjoy provoking strangers, and aren't terribly nice to acquaintances.
They command great power, but daylight weakens them. Actually, lots of things weaken them: garlic, silver, wooden stakes, patience, you name it. In spite of all that, they tend to be troublesome to handle.
Most vampires are members of aristocratic families or are otherwise extremely wealthy.