Envy is a homunculus who has the ability of shape-shifting. They use this power to assume the form of any person and even copy their voice. They usually serves as a spy, but their abilities are also extremely useful for assassinations. Envy may not be as smart as some of the other homunculi, but is by no means an idiot. In fact, they can be just as good a puppet master as Lust, but this is overshadowed by their cockiness and bad temper. Their temper can easily be set off by insulting their large and delicate ego, causing them to make mistakes.
Towards the very end of the series it is revealed that Envy was created four hundred years ago by Hohenheim in an attempt to resurrect the son he and Dante had, who later died from mercury poisoning when he was eighteen years old. Envy held a great hatred toward Hohenheim for never being acknowledged as his son and for abandoning him and Dante.
Beneath this cruel exterior however Envy is secretly envious of humans’ inner strength and the mutually beneficial friendships that they share, since most of the Homunculi show little real concern or emotional support for each other.