The Leanan Sidhe is a sort of vampire meets a muse. She attached herself to artists, poets, writers, and musicians and suck up all their creativity and left them bereft and depressed to the point of suicide. You know, like a groupie. Well, she'd come by with her big ol' cauldron and fill it up with their blood. From here she drank or bathed or soaked her cuticles or whatever to retain her beauty and intoxicatingly inspirational powers. I wonder if Oprah has a cauldron...
The Dullahan or "dark man" is a harbinger of death in a sort of Irish headless horseman tale. The headless Dullahan rides a black horse with fiery eyes while clutching his head beneath his arm. Wherever the rider stops, death visits hapless mortals. However, you can bribe the Dullahan with gold and he may spare your life. I wonder if he ever thought about running for office...
The Bean Sidhe is a more common entity in the list of Irish monsters, although you mightn't recognize the proper spelling. The "Banshee", as Americans term it, is a spirit that attaches itself to a family and wails horribly in anticipation of death with in the clan. And you thought your relatives were a bunch of loud mouths.
Ruling over the Fomori, a race of demons living deep in the lakes and seas, Balor was the sort of god of the underworld in ancient Celtic myth. He had one leg and one eye with which he could stare down a person to death. His victims were given over to the Fomori. Balor's own son, Lug, killed him with a slingshot (giant? slingshots? hmmmmm...) With Balor dead, the Fomori were free to evolve into sea monsters and seek out their own human prey, which is pretty much how I see the whole Kate Plus 8 thing working out.
Sluagh are dead sinners that come back from the dad to hunt down souls. They arrive from the west (like so many tourists, probably landing in Shannon) in flocks and attempt to gain entry into the homes of those knocking on death's door. It was tradition among some to keep west-facing doors and windows shut at all times.
Carman was an witch-goddess in Celtic lore. Like an evil stage mom, she traveled about with her three sons: Dub, Dother, and Dain (the Irish words for Darkness, Evil, and Violence). Together they destroyed anyone or anything in their path. Eventually, Tuatha De Danann (the people of Danu) defeated the old witch with powerful magic and banished her kids across the sea-probably to America. Thanks.
Kelpies are shape-shifting sea monsters that often appear as a horse. The horse would come from the sea, ride across the land, and entice victims to ride him. Once mounted, the Kelpie would race to the sea, dive in, and drag the victim down to its lair whereupon it would be quickly eaten.
Caorthannach was banished from the emerald isle when St. Patrick was running his pest control service. This fire-spitting beast (a dragon some say) didn't want to go so easily, but St. P was able to do the job. With one word. That's how badass he was.
Source: http://spellscasting.blogspot.com
