Barry the Chopper was once a famous serial killer who was thought to be executed, but his soul was bonded with a suit of armor and charged with guarding Laboratory 5.
Barry the Chopper was a former serial killer who was responsible for the deaths of over 20 people. When he was executed through hanging, his soul was put in an armor and his body was reanimated in a secret location.
Depending on the series of Fullmetal Alchemist, there were changes with the voice actors. For instance, in the 2003 version of the series. The Japanese version had Barry cross dressing as a woman, and he was voiced by a female voice actress while in disguise. The U.S. version of this series only had him voiced by a male voice actor doing a female voice. In the 2009 Fullmetal Alchemist series, we never meet Barry before he is in his armor body, but later his still living body is introduced and possessed by an animal's soul. In both the English and Japanese versions of this anime, Barry is voiced by two different voices for the armor and real bodies.