Holy energy is the special kind of magic energy, used by holy spirits and beings of light. Holy energy is often used for healing and protection spells, but can be used offensively as well, useful against beings of evil and darkness. The holy energy origins from unknown gods and godesses of light, and can only be cast when in contact with them, which is nearly impossible, or at least difficult to be, when surrounded by complete darkness. 

If any creature is overloaded with holy energy and fel energy at the same time, it will explode.