Dark and Light Black and White Shade and Light one cannot exsist without the other. Both are different phases of the same Energy. Light actually cast's the Shadow. One cannot stay in the shade forever though there are prices.
None can use black Magick without straining the soul to the uttermost—and staining it into the bargain. None can inflict suffering without enduring the same. None can send death by spells and sorcery without walking on the brink of death’s own abyss, aye, and dripping his own blood into it. The forces black Magick evokes are like two-edged poisoned swords with grips studded with scorpion stings.
So avoid the sting avoid the poison and seek balance. For within balance of the light and the dark one has obtained mastery of the growing Cycle and can continue to grow and evolve and transform as light does to shadow and shadow to light.