Well, it differs between people. Kara, another friend of mine, uses different metals to produce different effects. She calls the process of using them 'burning' the metals. For most of us, however, our abilities come through the application of Anima, which is the life force of our world, or at least comes from it.But that's specific to my world in particular, or at least as far as I am aware. I suspect that this may not be the case for humans from realities different from my own.