Irregular Mana
Mana is something that cannot be stolen nor can be made artificially. Mana is something that resides in each and every person. The only difference that separates mages from the general populace is that mages have compatibility on the elements and convert their mana into matter.
But it was not as simple as that.
People who were born with average mana and no compatibility to be mages cannot be mages. It is widely believed that their 'souls' have something to do with it.
Sorcerers are known as humans with magical prowess—people who can use incantations in various forms such as battle, healing, and research. They say on ancient texts that sorcerers are born from a reincarnated soul of an Elf, an undying creature. Books of older origin suggest that the souls of elves who are perhaps murdered found their way to inhabit a human baby's body.