"Umbra Sprite means simply, dark spirit, but the Grackleflints are utterly my own creation. In searching for a moniker for a brood born of a demon, I devised the term in the same way I came up with Matchstick ­ by combining common words to form a character name that was descriptive. Grackles are oily, squacky, nasty birds. Flint is brittle and black ­ like their souls. Making them featureless and white stressed the point by formajg an opposite image. Otherwise, there's no mythological base for these characters ­ although there are certain mentions in Native American lore about hideous old women with sharp, spiked elbows."