The original three elements of the world when it was created by Bartleby and Raven were Fire, Ice and Storm. Life came along when the first creatures began to multiply. Death came when the first creature in the world died. And Myth came when the first story was told.
Balance only really manages the balance between the core elements of the universe and, as a result, they cannot yet control the more diffuse elements of Life, Death and Myth - but, they are capable of boosting or weakning people to those elements. The reason is that Life, Death and Myth all act with the very spirits of creatures and people, making it extremely difficult to cast - whereas Fire, Ice and Storm are the pillars of the universe and will always be the same, no matter where in the Spiral you are, and no matter if there are creatures or not.
Maybe in the future, when more secrets of the ancient order of Balance has been found, those of the Balance school may be able to wield spells that come from the Spiritual sides of the Spiral, rather than, as it is now, only the Elemental sides.
The best you can do as a Balance student is to help examine the many ancient scrolls of Krokotopia; study hard, and perhaps you can unlock some of the secrets of this mysterious school we still know so little about.
I think it's because of where Balance originated: Krokotopia. I'm not sure if this is exactly right, but I think when the Kroks took advantage of the Manders' hospitality, they enforced their rule with Elemental magic (Fire, Ice, and Storm). Some Kroks saw the error of their ways and broke away from the malicious Krok rulers to form the Order of the Fang. They realized that their resistance wouldn't be tolerated by the Krok rulers and that the Fang wouldn't stand a chance facing the powerful weapon they possessed. This led them to create Balance magic, a magic that was born from drawing together the Elemental magics and finding balance between them. The Order of the Fang then used this weapon, infinitely stronger than the individual Elemental magics, to put the Kroks in a deep sleep.
What about death life and myth 
