But I find it necessary to repeat in this particular place that the division into classes, which is so salient a part of modern demonology, had, and has, little significance for primitive man or for the peasant in a comparatively low state of mental development. To such people, spirits of all kinds - fairies, the ghosts of the dead, and even witches and water-kelpies - are all creatures of the supernatural class between which he scarcely differentiates.
Lewis Spence, British Fairy Origins
fairies, fairy, kelpies, spirits, supernatural, witches