When a Will o' the Wisp has fed upon enough blood, it matures into an Adze. Traditionally, this took decades, as the Gremlins and other swampfiends that the Wisps fed upon provide it with little nourishment. Something about human blood, however, triggers a greatly accelerated growth process in the Wisps. Upon reaching maturity, the magical skills of an Adze increase significantly, making it a far greater threat than its immature kin.