Lords of Creation: Ancients of the Void
Transmutation is the art of magic of turning on thing into another, this can range from giving creatures who breath are gills to breath underwater, or altering a piece of wood into metal. The greater the change is, the more power and mastery it takes to accomplish.
The range of possibilities for Transmutation is great. but this magic is especially difficult to master due to the versatility and the knowledge required to fully utilize it.