Everyone knows the power of the Philosopher's stone. Few have witnessed it. Many have died from it. The power of the Philosopher's stone has been abused for generations. Human sacrifice is the main ingredient for making one.
The Philosopher's Stone is known as the Red Stone and the Fifth Element. It is a powerful transmutation amplifier. With it, an alchemist can bypass the law of equivalent exchange.
Homunculus... Stories of immortal monsters told to us by our Grandparents... odd beings made by a "Father" 100 years ago using a Philosopher's Stone.. Completely wiped out by a small group of alchemists and militia... Or so they thought... with one still alive, an Experiment of Father to recreate himself in the Flask, a new set of Homunculus have been born and now their Rebellion has begun.
The Homunculus are being reborn now and getting stronger than ever, creating new Philosopher's Stones at the cost of thousands of lives. Rumor has it that they are generating a new stone using the souls of humans. The stone is called Seal of Suitai also known as Seal of Oblivion.
This Seal of Suitai grants the Homunculus the ability to use alchemy making them more of a threat to the Military and Civilians. The Military has been doing all they can to keep word of this away from the public so there isn't a panic while they follow the trail of the Homunculus and take the Suitai out of their grasp. However, word has gotten through to civilians causing them to rebel against the Military to find the Seal of Suitai to use themselves and research it on their own.