I can't let Halloween go by without another entry in the Dark Fey series, can I?
(Disclaimer: This is the non-undead monster from B/X, not the AD&D undead of the same name. I figured it fits pretty well among the dark fey.)
What's that? You wish to hear another tale? Not so keen to head out toward home, are you, even on such a clear crisp evening as this? As well you might not, what with the moon at its full and the shadows reaching their long arms across the earth...No, hardly a fit night to be abroad. Another pint, then?
Well then. Where was I? Ah, yes. No, you needn't be afraid of your own shadow. But when you finally walk home tonight, to your family and your bed, you'd best have a care that the shadow that follows you truly is your own. There other things that cast shadows, things no longer of this realm.
Did you know that even among the fey, there are crimes too horrible to countenance? Yes, the wild and perilous fey, to whom the snatching of babies from their cradles and blasphemy against the gods themselves are worth scarce a first thought, never mind a second! What enormities could so horrify them? I know not, nor do you, and pray the gods will it we never should learn!
Only the fey themselves know, and it's a dire business indeed when one of their kind should be deemed guilty of such hideous misdeeds. And what punishment could be meted out against soulless folk, who live on and on without end, to whom neither the gallows nor the headsman's axe holds any menace? Nothing short of eternal banishment! Not from a village, or even a kingdom, but from the world of the living itself. For an instant, on moonless nights, the sorcerers of the fairy court may tear back the veil between the worlds, and through that awful rent are cast the condemned, those irredeemably monstrous beings, and there they sit to brood and hate until time itself should crumble away and all barriers fail.
Yet even there, they are not wholly powerless, and from time to time they may still work their malice upon mortal and fey alike. For theirs is a prison not of solid walls, but of silken curtains. When and wherever light shines in our waking world, so it shines in that queer place also, and through the veil it projects the shadows of those fallen wretches.
In full darkness no shadows are cast, and in the noonday sun they are but shrinking things, huddled close about the feet of wall and tree. In twilight, though, the shadows come into their full. Then the shades skulk and creep, blending with the shadows of our world, stalking mortal folk. If you're lucky, they may do no more than that, watching you with ill intent unfulfilled. Out of the corners of your eyes, you may catch glimpses of shadows that mismatch the things which seem to cast them, or move in unnatural ways, when naught else moves to pull their strings. And then, my friend, you would be well advised to get you at once to a place with lamps all around to disperse the shadows, or failing that to douse your light and sit huddled miserable in the darkness until the sunrise.
For if they catch you, they will reach out their long shadowy arms and touch you! A touch from beyond this world, to chill the blood and the marrow of your bones, but more than that, to pull your soul, bit by bit, into that nether place, to sit beside the flesh and bone of that very thing which casts that dreadful shadow. If you should manage to resist or to escape its clutches ere it takes the last, the lost bits find their way back in time, and you'll be well and whole again, and none the worse for the ordeal.
But beware! Should the last piece of you fall into its greedy grasp, then it draws you through the barrier, body and soul, and there you shall dwell with it, forever in its thrall, your mind shattered and mad beyond redemption - casting your own terrible shadow through the veil.