Next to these Gods, a wise man will do service to the daemons or spirits, and then to the heroes, and after them will follow the sacred places of private and ancestral Gods, having their ritual according to law.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz
When he proved himself absolutely his own master, when his teachers were certain that he could not be dominated by another will or by any outside or psychic influence, then for the first time he was permitted to exercise his own iron will in controlling daemons, ghosts, and all the elemental hosts of the air-either as a white magician or as a black magician.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz
But they were quite scientific in their methods, for they divided all invisible beings into four distinct classes: the Angels, who in character and function are parallel to the gods of the ancients, and equal to the Tuatha De Danann of the Irish, are the highest; below them are the Devils or Demons, who correspond to the fallen angels of Christianity; the third class includes all Elementals, sub-human Nature-Spirits, who are generally regarded as having pygmy stature, like the Greek daemons; and the fourth division comprises the Souls of the Dead, and the shades or ghosts of the dead.
"The Fairy-Faith in Celtic Countries"
W. Y. Evans Wentz