The story of Fullmetal Alchemist: Brotherhood is a deep one, packed with themes of the cycle of vengeance, sin and forgiveness, the price of ambition, the dual nature of humanity and more. It also has some amusing quirks.

Edward and Alphonse Elric are the sons of Van Hohenheim, the wandering alchemist, and when they come face to face with Father the villain, they are in for a shock: Father looks just like Hohenheim. Father also has seven other "children": his homunculi. That revelation means that Edward and Alphonse are closer to the homunculi than they realize.

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Slave #23 Gains a New 'Brother'

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Over 300 years ago, in the desert kingdom of Xerxes, a strange creature was contained in a glass flask: a tiny homunculus, its origins unknown. It was the "dwarf in the flask," and one day, it spoke to a gold-haired slave boy known as Slave #23. Crafty and ambitious, the "dwarf" made friends with this slave and even gave him a name, Van Hohenheim, to empower him. It convinced Hohenheim to learn alchemy from a master and buy his freedom, and its ambitions rapidly grew. He had a massive transmutation circle dug around the entire Xerxes city-state, all to grant the Xerxes king immortality (or so he said).

Hohenheim, when instructed, gave the "dwarf" his own blood sample and the transmutation began. But it was all a trick: all the Xerxian people save for Hohenheim were sacrificed to the ritual, and with Hohenheim's blood sample and 500,000 Xerxian souls in him, the tiny homunculus became Hohenheim's twin in his genes and body alike. Needing to purge himself of all human sin to further his grand scheme to become a new god, he became Father.

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Ed & Al's Strange Family Tree

That's a grisly tale, but this is where it becomes amusing. Hohenheim and Father are effectively twin brothers -- since they have the same DNA and each contains half the total Xerxian souls in them. Father created his seven homunculi, one for each deadly sin, from his own essence. As Pride, the firstborn, explained it, the seven and Father are ultimately the same being, just in different bodies. Elsewhere, many years later, Hohenheim married a human woman, Trisha Elric, and had two sons with her. These boys inherited their father's unique gold hair and eyes, and they're related to Father.

In another theory, Father might be considered Hohenheim's son instead, since Father was created from Hohenheim instead of alongside him. Genetically, they are twin brothers, but if Father may be considered Hohenheim's son, then that means the seven homunculi are Hohenheim's grandchildren. This would also mean that Ed and Al are Father's cousins, and by extension, they are uncles to the seven homunculi, despite being much younger. It's a weird connection that even Fullmetal Alchemist's creator has jokingly pointed out. This family tree is based on the generations at play, rather than the age of each character; in this case, a person might have an aunt or uncle who is younger than they are. Such things can happen, especially when Philosopher's Stones are involved.

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