Saint Diadochos distinguishes evil spirits into two categories: into the most subtle psychic demons and into the most material carnal demons. The subtler spirits fight the soul by arousing the psychic passions and the material fight the flesh by arousing the body with carnal desires. Both categories are equivalent, yet they operate "against each other", due to the difference between the soul and the body, which is reflected in both categories of demonic spirits, as long as they affect the soul and the body. When grace does not dwell in man, they nest in the depths of his heart, like real snakes, preventing the soul from desiring good. But when Grace, which was obtained through Baptism, is in man, then they run around the parts of the heart, that is, not in the heart or mind but mainly in the flesh, like dark clouds, taking various formations, in order to distract the mind from its contact with Divine Grace.1
