" A ghost is the echo of a tragedy—a hologram, almost, left over from a traumatic death. A spirit is the very essence of who we are, without our earthly bodies. It is the part that crosses over when we die. It is not supposed to linger on earth, though there are ways of ensuring it does. Eris seems to have bound the spirit of her worst enemy to earth, and she plans to destroy it, in order to complete the third ritual. "

― Bella Forrest , Harley Merlin and the Cult of Eris (Harley Merlin, #6)