Hohenheim and Edward in “Unfinished Business”

This world is tragically violent. Throughout the course of this war millions of people have been killed with the use of highly toxic gases, but the single most terrifying instrument of death is yet to come. You saw it in the gate, didn't you? [Edward remembers an image of the atomic bomb cloud above Nagasaki.] The lives of those that have died and will die in this world become the energy for the alchemy used in ours.

Edward

The energy? That doesn't make sense...What about the-

-law of Equivalent Exchange? There's something you don't understand. It takes more than equal mass to restore a broken radio. The energy used to put it back together must come from somewhere, too. And energy cannot be created or destroyed; only redirected.

Edward

So that's the secret? The lives of the people who die here cross the Gate and become energy we need for transmutations? Is that what you're telling me?

Inside all of us there lies a smaller version of the Gate you passed through. Alchemists have the ability to open their Gates, crossing worlds and feeding off the tragedies of this one. It happens every time you draw a circle or clap hands.

Edward

You sound just like that head case Dante! All the same crap about there being no Equivalent Exchange!

I wasn't aware you knew about her.

Edward

I know everything! I know the two of you were lovers because I read the letter. I know you've been keeping yourselves alive jumping from one body to another. But what I don't understand is if you and that evil bitch were so perfect together, why did you feel the need to marry my mother?! Did you get some sick satisfaction out of pretending to be a normal human?!

I loved your mother. With all of my being, I had never loved until her. You have to believe that.

Edward

Then why?! Why did you leave us?!

[Pulls up his sleeve to reveal decaying flesh.] I just couldn't let you see me like this. The thought of it was too much for me to bear.