Forms of evil by St. Maximos the Confessor

Among the demons, says the blessed Dionysios, evil takes the form of mindless anger, desire uncontrolled by the intellect, and impetuous imagination. But mindlessness, lack of intellectual control and impetuosity in intelligent beings are privations of intelligence, intellect and circumspection. But a privation is posterior to the possession of something. There was a time, then, when the demons possessed intelligence, intellect and devout circumspection. This being the case, not even the demons are evil by nature, but they have become evil through the misuse of their natural powers.