The Immortal Legion
The Mannequin Soldiers awaken and kill the general. As Ed's group arrive at the door where Al had fought against Lust, the mannequins emerges from the door and they turn out to be immortal indeed. Meanwhile, Olivier is attacked by Sloth, who had been ordered to kill her. Al and Heinkel learn too late that Pride had been sending a secret message from banging on Al's head and are soon attacked by Kimblee, who frees Pride from his imprisonment. In the sewers, May is also being attacked by mannequins and when Envy manages to merge with them, he is able to return to his regular form. As Olivier struggles against Sloth, Alexander rescues her and joins the fight. Al transmutes his legs off in order to help Heinkel, who then gives him the Philosopher's Stone that Kimblee previously discarded. Al uses it to restore his legs and face Pride and Kimblee.
Aired 04/04/2010EP 51 - The Immortal Legion
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)