Fullmetal Alchemist: Fullmetal Edition, Vol. 15

In an alchemical ritual gone wrong, Edward Elric lost his arm and his leg, and his brother Alphonse became nothing but a soul in a suit of armor. The brothers' final battle begins, and their first confrontation is with the homunculus Pride, who is controlling Alphonse from within.

Fullmetal Alchemist: Fullmetal Edition, Volume 15, by Hiromu Arakawa.