MoP has introduced various spells, including Malefic Grasp or Twilight Ward that contain the twilight descriptor. That school of magic was frequently used in Cata by the Twilight's Hammer, several dragon and Old God creatures. However, concrete information is nowhere to be found regarding the nature of this magic and its exact definition.
What are your thoughts and theories about what is the core idea of this school and how it is applied by Warlocks in terms of lore?