Scar and Edward in “Unfinished Business”

Scar

Knowing what I do now, I understand why.

Edward

I talked to the Exile. He told me about the method. The Grand Arcanum circle takes an even greater human sacrifice.

Scar

It's true. An entire major city would have to be turned to an open grave or an entire race of people wiped from the face of the planet. all those souls displaced, angry, still crying in sorrow at their loss, are pulled into the array and form the Philosopher's Stone. In a cruel paradox, the Philosopher's Stone was the only way to save Ishbal, and yet it would take the entire genocide of its people to create it.