Soul Burning

[Technically, your soul could be used instead of mana. Sure it would hurt like hell and sure it would probably debilitate you beyond saving, but it would work. You probably don't know this, but way back in the past, the people who could see mana were pitied by the people. A sad bunch of madmen, who would continuously talk about some colorful blue stuff. After all, no one in the World knew what magic even was, so there really wasn't a big difference between mages and non-mages. All those stories from your home planet Earth, which usually depict ancient wizards and witches being much stronger than their modern counterparts... Well, logically thinking, it just isn't plausible, as shown by the example here on Alvox.]