...Yeah. Bringing a human back from the dead, creating a human that never existed- that's human transmutation. And it's forbidden because it's not even possible. And there's a price you have to pay even if it doesn't work.

[She leans back, crossing her arms, visibly uncomfortable.]

The greater the loss, the more you want it. And the greater price that you pay for it, too. Performing human transmutation takes you to the Gate of Truth- the source of all alchemic knowledge, something that exists in every human being. There's this creepy guy who hangs out there- Truth, or God, or "The World"- he's really unclear about what the hell he is. But he makes a trade with the alchemist: they get to see inside the Gate, and they give something up in return. Al and I tried to bring Mom back, and I lost my leg. Al... lost his whole body.