Not sure if this has been discussed/or is already obvious... But I thought about something.
(If it's been discussed I'll delete this)

Okay, so as talked about in a recent post, the homunculus come from beyond the gate, so the theory was brought up about when you raise someone, you're actually pulling their alternate person from beyond the gate. I liked that theory, and it crossed my mind earlier.

What's inside the gate? Our world, but what purpose does it serve? The lives from our world flow through the gate as energy for alchemic reactions. That much is known. My theory is basically this.. Do you think those faces and eyes inside the gate are actually the dead souls of people from OUR earth who are to be used as Alchemic energy?
They're the source of the energy, and I guess expanding this theory, they're the ones that will take things via equivalent trade (Al's body). And Wrath was from Amestris (Izumi's child), and was given to the gate. So he's been waiting as one of the souls from the other world, and once Ed entered he was able to take Ed's limbs. So basically, the souls from OUR earth become eligible pre-homunculus!



Also, check out my recent fanart! WARNING:EPISODE 50 SPOILER