A term that describes the multitude of creatures who seek power, glory, fear, envy, lust, vengence, domination, etc. and use whatever means necessary to get what they want; in other words, they are ruled by desire, and use desire to manipulate others. It is called "black" because it is corrupted by the ego, desire, attachment, etc.
"From the dawn of life, a great battle has raged between the powers of Light and the powers of Darkness. The secret root of that battle lies in sex. Gods and Demons live in eternal struggle. The Gods defend the doctrine of chastity. The Demons hate chastity. In sex is found the root of the conflict between Gods and Demons... There are Masters of the Great White Lodge. There are Masters of the Great Black Lodge. There are disciples of the Great White Lodge. There are disciples of the Great Black Lodge. The disciples of the Great White Lodge know how to move consciously and positively in the Astral Body. The disciples of the Great Black Lodge also know how to travel in the Astral Body... The White Magician worships the inner Christ. The Black Magician worships Satan. This is the I, the me, myself, the reincarnating ego. In fact, the I is the specter of the threshold itself. It continually reincarnates to satisfy desires. The I is memory. In the I are all the memories of our ancient personalities. The I is Ahriman, Lucifer, Satan." —Samael Aun Weor, The Perfect Matrimony
"Understand that every association of fornicators forms a black lodge, and each lodge or school of this kind has its boss or manager who they venerate as a saint or master." —Samael Aun Weor, The Major Mysteries