When Swift created Humans, he did so with the purpose of gathering energy from the planet to return to himself. Humans were created with magical conduits throughout their bodies that absorb abient energy from the planet. Standing in the sun causes them to absorb a small amount of energy from the light. Eating food causes them to store a small amount of energy, as plants and animals gather energy from their surroundings as well. Humans though, are the only beings that are able to conciously tap into this energy and manipulate it. Through the power of prayer, focusing on god, humans transfered a small amount of this energy back to Swift.
Mages originated from the teachings of Boonlike back in ancient times. He taught people about the true nature of the energy stored inside them, and how to manipulate it to their own advantage. Since this pure energy was conciousness based, it was possible to use conciousness to control the energy. Mages could use this energy to manipulate reality, mostly for destructive purposes. The energy can only be realized in forms of energy that actually exist. Electrical, thermal, kinetic, magnetic, and radioactive energies can be manipulated by a mage. When it's used as such, it's called Magic. The most powerful mages, and skilled wizards have the ability to control the energy within other people in a way that affects their conciousness. Since conciousness can be used to manipulate magic energy, it stands to reason that the reverse is true. This is a very dangerous and little practiced type of magic. One needs to completely dominate another person's energy within their own body in order to affect the mind. Very difficult when that person is conciously resisting.