Father is the creator of the Homunculus. Also an evil copy of Van Hohenheim, he's a creature who goal is to become the perfect being.
During the times of the ancient civilization of Xerxes, Father original form was a small shadow-like creature in a flask that was born from an unknown alchemist experiment that used the blood of a young slave known only as Number 23. The creation asked to be called a " Homunculus" and out of gratitude for the blood that brought him into the world. The creature then named the slave "Van Hohenheim". The Homunculus had a great amount of knowledge about the use of alchemy, which he had taught to Hohenheim. This knowledge had helped Van rise from a poor slave to associate alchemist to his master. Hohenheim had always wished for a family, but the Homunculus wished for a life outside of this flask.
In order to gain his freedom, the Homunculus had tricked the known King of Xerxes by promising him the power of immortality through making a transmutation circle that would surround his small kingdom. The dwarf kept the details of the plot from Honeheim that the cost would be the slaughter of the innocent throughout the land of Xerxes and took several years to complete. In the end, all of the people in Xerxes had their souls ripped from their bodies to create the 1st known Philosopher's Stone. The Homunculus had lied to the king about the center as it was standing at the true center with Hoheneheim.
He would awaken in a new vessel that was made to look like his apparent creator Honeheim and had divided the Philosopher's Stone with him to grant an immortal body. Van was horrified as he was surrounded by the bodies of his friends and neighbors that surrounded them both. They both had separated, The Homunculus traveled to the west and Hohenheim went into the East to the land of Xing. The Homunculus had planned to become the perfect being by taking the power of God, but would need to recreate the same plot had done in Xerexes, only on a far larger scale. He began by creating the small country of Amestris.and taught his form of alchemy to it's people. In his idea of perfecting himself, he separated the sins of his body into the embodiments called the known Homunculi, with a philosopher stone core in there body and they would called him by his known alias "Father". With these powerful creatures as his own family, they would create an army and manipulate the world to build the country and the transmutation circle for Father's plot.
Father is the main antagonists in the series Fullmetal Alchemist that was created by Hiromu Arakawa . The idea was originally serialized in Square Enix's Monthly Shonen Gangan magazine in August 2001.
Father's first appeared in Fullmetal Alchmeist Volume 8, CH. 31 "The Snake That Eats It's Own Tail", and his first anime appearance was in FullMetal Alchemist: Brotherhood - Episode 1 " Fullmetal Alchemist". In the Japanese series, he is voiced by Iemasa Kayumi, and the English dub produced by FUNimation he's voiced by Kent Williams.
Though Father has always been the intended main antagonist for the Fullmetal Alchemist series, he never appeared in the first anime series based on Arakawa's work.
In the beginning of the series, Father's actions are coordinated in time with Van Hohenheim's, lending some ambiguity as to the true perpetrator of the actions against Amestris. However, it is later revealed that Father is an entity separate from Van Hohenheim, during a chance encounter with the Elric brothers.