[There's a moment of silence, but he trusts Zell and it's incredibly important that he is made to understand that bringing people back isn't something to just charge into headlong.]

I was four when our Mom died, it was a sickness that swept across the country, it was so quick... Dad had already left and he didn't come back when Mom died, so it was just Brother and me. Our friend Winry and her Granny took us in, but it wasn't enough, we wanted our Mom back. We wanted her back so much...

[What idiots they had been.]

We'd already started practising alchemy, but human transmutation is something that's forbidden. Alchemy-- everything, is based on balance. Equivalent exchange, you can't make something from nothing, you have to give back an equal price. That's why making people was forbidden, there is no equivalent price, but we thought-- we thought maybe we could do it anyway. So we trained for a long time and researched everything we could find, and when I was ten we tried to bring her back.

We have all the ingredients for a human body, we thought if we added our own blood it would be soul data, but... but it went wrong. It wasn't enough, the price rebounded on us. Brother lost his leg and I lost my entire body, I would have died, but Ed gave up his arm to transmute my soul into this suit of armour and bind me to it.

[He hesitates, voice getting quieter.]

And even after all of that, what we made was barely even human. It was... broken, and bleeding, and it died again just a few seconds later.

We've met people since who can perform human transmutation using a philosopher's stone to bypass equivalent exchange, but those are made with human lives, using their souls for energy. I don't know if that's what's happening here, but I do know that people shouldn't come back from the dead, Zell, not ever.