Homunculus (The Dwarf in the Flask)
Olivier goes to Central, where she admits to killing Raven and convinces Bradley to let her take his place. Riza uses a coded message to tell Roy that Selim is a homunculus. Meanwhile, 'Father' dreams of ancient Xerxes, where Hohenheim was raised as a nameless slave. There, Hohenheim met Homunculus, a being in a flask who was created from his blood, which gave Hohenheim his current name and taught him the basics of alchemy. One night, Homunculus was summoned by the King of Xerxes, who asked Homunculus to tell him the secret for immortality. Homunculus tricked the king into making a gigantic transmutation circle, using the whole country as a sacrifice, while it and Hohenheim stood at the center of the circle. When Hohenheim awoke, everyone else in Xerxes was dead, except for Homunculus. It created a body shaped like Hohenheim for itself, becoming 'Father.' Back in the present, after Hohenheim awakes from this shared dream, he runs into Izumi and Sig. When Hohenheim notices Izumi's sin, he rearranges her organs so that her blood can flow better. After this, Hohenheim tells Izumi and Sig that he is a Philosopher's Stone in human form.
Aired 17/01/2010EP 40 - Homunculus (The Dwarf in the Flask)
Fullmetal Alchemist: Brotherhood
"In order for something to be obtained, something of equal value must be lost."
Alchemy is bound by this Law of Equivalent Exchange—something the young brothers Edward and Alphonse Elric only realize after attempting human transmutation: the one forbidden act of alchemy. They pay a terrible price for their transgression—Edward loses his left leg, Alphonse his physical body. It is only by the desperate sacrifice of Edward's right arm that he is able to affix Alphonse's soul to a suit of armor. Devastated and alone, it is the hope that they would both eventually return to their original bodies that gives Edward the inspiration to obtain metal limbs called "automail" and become a state alchemist, the Fullmetal Alchemist.
Three years of searching later, the brothers seek the Philosopher's Stone, a mythical relic that allows an alchemist to overcome the Law of Equivalent Exchange. Even with military allies Colonel Roy Mustang, Lieutenant Riza Hawkeye, and Lieutenant Colonel Maes Hughes on their side, the brothers find themselves caught up in a nationwide conspiracy that leads them not only to the true nature of the elusive Philosopher's Stone, but their country's murky history as well. In between finding a serial killer and racing against time, Edward and Alphonse must ask themselves if what they are doing will make them human again... or take away their humanity.
(Source: MAL Rewrite)