Baobhan Sith

Baobhan Sith are malevolent spirits from Scottish folklore (though variants can also be found in Irish mythology), they are often considered a type of demonic fairy and are also often believed to be the inspiration for many vampire tales in the region, though the phenomena of vampires is a complex one with almost every culture on Earth having regional variants (to the point there is an entire family of monster known as Hematophagic Monsters).

Due to their seductive natures they are quite popular and appear in numerous media outside of their native folklore, commonly acting as antagonists due to their evil nature.

History
Baobhan Sith are legendary monsters found in Scottish folklore and are depicted as beautiful women who often appear in secluded areas, dancing and singing (almost always appearing in a group, it is considered extremely rare for a Baobhan Sith to appear without at least one other, making them in many ways a pack predator) - they will invite men to dance with them and seduce them, if a man is foolish enough to accept their advances the Baobhan Sith will transform into a horrendous hag-like creature with inhuman strength and violence, in this form the Baobhan Sith proceed to mutilate the victim, drink his blood and then descend into the night in search of a new victim.

Their practice of drinking blood made them associated with vampires while their inhuman beauty and seduction skills made them similar to succubi and other demons, due to their tendency to haunt secluded areas and due to their use of dance and song they are also often considered a type of malevolent fairy.

To ward such creatures off one could either rely on traditional folk charms to ward of fairies and other malicious spirits (such as horseshoes or cold iron) or alternatively use holy relics such as the bible and prayers to combat them (though in some stories the use of Christian prayers drove them into a frenzy): like many spirits they also could not cross rivers or streams, thus if one was able to cross such an obstacle in time they could theoretically survive but very few accounts exist of someone surviving long against these exceptionally clever and dangerous creatures.

As well as chance encounters with these creatures are a common theme found in many legends is that they may also manifest whenever a man wishes for female companionship during the hours of night (based on old superstitions) - such a tale was told in which a group of hunters retired to a cottage one night only to be doomed when one of the men wished for female companionship, sure enough within a few moments a group of attractive females arrived and asked to stay with the men only for a bloodbath to follow when the females revealed themselves to be Baobhan Sith in disguise. However, one man managed to survive (defying the usual fate of such victims) by hiding between three horses for the night, it is believed that the Baobhan Sith could not attack him because of the iron in the horse's shoes acting as a barrier, though he paid a terrible price for such survival as he had to watch as the monsters killed his entire hunting party, only leaving once sunlight began to enter the sky - causing the Baobhan Sith to flee.