Fullmetal Alchemist

Synopsis

The Elrics learn that the guards are souls bound to empty suits of armor. Ed struggles in his battle against Number 48, a serial killer known as Slicer, When his automail arm malfunctions, the result of Winry forgetting to add a small bolt. Ed is troubled to see that his opponent is a pair of brothers, where the younger one controls the body. Ed manages to defeat Slicer by use of Scar's destruction technique, yet he refuses to finish them off, due to seeing Al in the same manner. Al realizes that Number 66 is Barry the Chopper, who tries to suggest that Al never truly existed, saying he was a doll made for Ed. Contemplating on the possibility, Al recalls that Ed was afraid of telling him something.

(Source: Wikipedia)