Succubus - The succubi are a direct result of the demonizing of Lilith. As a remedy to the curse of infertility and death, the succubi - female - seduced men, disguised themselves as men, and seduced women - preferably virgins and nuns as a joke - stealing the demonic infants away in the night. These infant creatures became - you guessed it - the vampires.
Pisces is a Mutable sign, and therefore able to adapt easily to the world around them. Like water, Pisces morph to fit the situations in which they find themselves and can therefore sometimes lack a defined sense of identity.