Fullmetal Alchemist’s power system is governed by the laws of the ancient practice of Alchemy, and despite being based on scientific principles, this power bears a more sinister side that is usually glazed over. While Alchemy deals with the transmutation of inanimate objects, some Alchemists have dared to play god by transmuting living humans and their souls, giving way to various forms of forbidden Alchemy.

All forms of forbidden Alchemy stem from Human Transmutation, be it resurrection of a dead human or binding the soul of the deceased to an object. Despite being deemed as Taboo, these forms of Alchemy have been attempted by rogue alchemists and the state of Amestris itself. However, the catastrophic results of these transmutations prove exactly why these transmutations were classified as forbidden in the first place.

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Human Resurrection

Using Alchemy to Bring the Dead Back to Life

Human Transmutation has been used for all manner of bizarre experiments, yet resurrecting the dead is considered to be the worst folly. Despite being attempted out of pure intentions, resurrecting a human soul has catastrophic ramifications, all of which are rooted in the Principle of Equivalent Exchange. The Rebound caused by such a transmutation often ends in death for the alchemist, with every instance proving this effect.

Once the soul has left the mortal realm, it is impossible to bring it back into the living world, a system that essentially makes it impossible to revive the deceased. Attempting human resurrection will always result in a failed transmutation, yet it will still cause a Rebound. This Rebound not only takes into account the price of bringing the dead back to life but also exacts punishment for anyone audacious enough to play god.

Human resurrection is a significant driver of Fullmetal Alchemist’s plot, as Edward and Al’s journey only starts after their failed transmutation to bring back their dead mother. The transmutation took Alphonse’s entire body and Edward’s leg based on the Principle of Equivalent Exchange.

Homunculus

Producing Artificial Humans Through Alchemy

Homunculi are artificial humans created through Alchemical transmutation. In the world of Fullmetal Alchemist, however, the notion of creating a Homunculus had become an almost fictional concept, especially since Alchemists had failed at successfully creating an artificial human. Even with no successful attempts, Amestris has banned research and experimentation on Homunculi.

Despite being a myth, seven of these creatures roam among the people of Amestris, with these Homunculi making up the series’ primary antagonist faction. However, the seven Homunculi were not formed through regular Alchemy, as their roots lie in the Philosopher's Stone’s power, coupled with Father’s own arcane power.

Chimeric Alchemy

Creating a New Creature Out of Two Life Forms

Chimeric Alchemy itself isn’t a forbidden form of Alchemy, yet the Taboo lies with incorporating human beings into the mix. While this form of Alchemy also treads on the darker side of things, the Amestrian government has been involved in creating animal-human hybrids, though none have been able to achieve human speech and cognition.

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Shou Tucker, a bio-alchemist, was one of the first Alchemists to successfully transmute a human and animal into a Chimera. While this form of Alchemy is also sacrilegious, it doesn’t seem to have the same repercussions as human resurrection. Given its heinous nature, Chimeric Alchemy involving humans is banned among the Alchemists of Amestris.

Soul Binding Alchemy

Binding a Human Soul to an Inanimate Object

While the concept of Soul Binding Alchemy seems akin to human resurrection, it is deemed a less severe sin, as it only brings back the soul of the human as opposed to bringing the entire person back to their original form. However, this form of Alchemy also taxes the Alchemist, as Edward had to sacrifice his arm to bind Alphonse’s soul to a piece of metal armor. It is believed that the iron found in blood attaches to the iron in the vessel, forming an alchemical bond strong enough to harbor a soul.

However, Soul Binding experiments have rarely been successful, with Alphonse’s Soul Binding being one of the rare cases of a highly successful transmutation. His Soul Binding was only successful due to both brothers being pulled into the Gate of Truth. Moreover, Alphonse’s soul is more unstable and easily malleable, allowing him to transfer consciousness among various parts of his armor.

Soul Binding is also quite volatile, as the soul is bound to an object that has no connection to it, meaning the two will eventually reject each other and separate. Still, Soul-Bound humans have the advantage of existing on the mortal plane without being held back by human weaknesses. However, due to the unstable nature of bound souls, coupled with the heavy toll of conducting this transmutation, practicing Soul Binding Alchemy is forbidden within Amestris.

Fullmetal Alchemist is available to stream on Prime Video.

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