Envidia, known in English as Envy, is a central antagonist representing the sin of jealousy. As a homunculus, Envy was artificially created, serving as a physical manifestation of the emotion of envy extracted from the being known as the Dwarf in the Flask. This makes Envy one of several homunculi, each embodying one of the seven deadly sins.

In terms of physical appearance, Envy most often takes the form of an androgynous, youthful-looking person with long, dark hair that can appear black with hints of green. The preferred humanoid form has a slender build and sharp, often mocking facial features. True to the nature of a homunculus, Envy bears the Ouroborus tattoo, the symbol of eternity and rebirth, located on the outside of the left thigh.

Envy’s primary and most defining ability is shapeshifting. This power permits Envy to perfectly transform into any person, animal, or even create original human forms. This is not merely a physical change; Envy can accurately mimic the voice and mannerisms of a target, making the disguise nearly impossible to detect without special sensitivity to the unique presence of a homunculus. This shapeshifting is often used to cause chaos, impersonate authority figures, or lure victims into a false sense of security. Beyond complete transformations, Envy can partially shapeshift, altering limbs into blades, tentacles, or other weapons for combat. When a significant threat is posed or Envy is cornered, the homunculus can shed its human guise to reveal its true form: a massive, grotesque reptilian beast. This monster is enormous, with a serpentine body, multiple legs, and most disturbingly, the faces and limbs of countless humans protruding from its entire body, screaming in agony. This form is a physical representation of the Philosopher's Stone at Envy's core, comprised of the sacrificed souls of the ancient civilization of Xerxes. If the Philosopher's Stone is nearly depleted, Envy devolves into a final, helpless true form, a small, worm-like or grub-like creature with a sucker-like mouth.

The personality of Envy is one of the most cruel, vicious, and sadistic among the homunculi. Envy holds humans in utter contempt, viewing them as weak, foolish, and easily manipulated lower creatures. This belief is not passive; Envy actively delights in psychological torment and suffering. The homunculus does not simply kill, but makes a point to toy with victims, often transforming into a loved one to inflict maximum mental anguish before delivering a fatal blow. Despite this arrogance, Envy is also hot-tempered and has a fragile ego, easily provoked by insults or setbacks. This emotional instability often leads to rash decisions and underestimation of human opponents, which eventually contributes to Envy's downfall.

Envy’s motivations are rooted deeply in the namesake sin. While outwardly professing disgust for humanity, the core drive is a profound and hidden jealousy of humans. Envy despises the human spirit that, despite being fragile and prone to failure, repeatedly gets back up, forms bonds, learns, and grows. This is something a homunculus, an artificial being born of a fixed purpose, cannot truly do. For example, Envy takes immense pride in being the sole instigator of the brutal Ishval Civil War, having disguised an Amestrian soldier to shoot a child, all while marveling at how a single bullet could make humans slaughter each other. This act was not just for a strategic purpose but for the sadistic pleasure of seeing humanity at its worst. Envy also personally murders Maes Hughes after the officer discovers a secret that could threaten the homunculi’s plans, killing him while disguised as his wife to savor his horrified hesitation.

Within the story, Envy serves as a recurring and formidable obstacle for the protagonists, often acting as a spy and agent of chaos. Key relationships fuel Envy’s hatred. The older half-brother of Edward and Alphonse Elric is one version, and even in the main continuity, a deep-seated jealousy of their bond with their father, Hohenheim, and their unwavering determination exists. Envy also holds a notable dislike for characters like Ling Yao and Lan Fan, who can sense the unnatural presence of a homunculus, thus piercing the deceptions. There is also a sense of strained family ties with the other homunculi, often bickering with siblings like Lust or Gluttony, but ultimately serving the collective goal of their creator, Father.

Envy’s development culminates in a moment of forced self-reflection. After being brutally defeated by Roy Mustang, who is seeking revenge for Hughes’s murder, Envy is reduced to its small, helpless larval form. Edward Elric steps in to stop the vengeful killing, showing compassion for the pitiful creature. In this moment, Edward realizes the truth: all of Envy’s cruelty and contempt were a mask for a deep, unbearable jealousy of humanity’s strength of spirit. When Edward openly expresses this pity and understanding, Envy is mortified to be seen so clearly by a human, especially a child. The revelation that its entire existence is driven by this pathetic, all-consuming jealousy is too humiliating to bear. In a final act of spite and despair, Envy tears out the Philosopher's Stone that serves as its own core, committing suicide rather than accepting the pity of a human. This end is the ultimate expression of the character's sin: self-loathing so profound that it can only find resolution in self-annihilation.