The Subatance is what holds all life and magic. Erec can see it through his dragon eyes, as can all dragons. It is what is needed for magic and life.
Sorcerers perform great magical feats by using the Substance. All beings have absorbency, or oneness with the Substance. The more absorbent you are, the greater power you have inside you. By visualizing what they wish to accomplish, sorcerers can direct the power of the substance with either a finger, an incantation, or a remote control, sometimes a combination.