Magic

Magic in the Magica Universe are forces created from fluctuation of emotion, unbounded by the First Law of Thermodynamic. When QB's scientifically-advanced civilization discovered Magic, they realized Magic's capacity to create new energy can postpone maximum Entropy and delay the heat death of the Universe. However, QB's civilization are incapable of emotions, thus they scoured the Universe for species with the most emotional potential. QB found his answer in the Earth's human females, especially those still developing secondary sex characteristics. Mahou Shoujo and Witches, thus the settings of the story, are the result of QB's quest to harvest this energy.