King of Xerxes

Known by history as the last Xerxesian monarch, the King of Xerxes, the ancient and prosperous land, ruled over his subjects well into his old age, acting in a manner that caused him to be beloved by the happy citizens.

However, fear of his approaching death and a presumed lack of eligible heirs began to cloud his judgment as he grew older and, when one of the nation's most prominent Alchemists produced an artificial life form with knowledge of arcane rituals and phenomena unheard of in the realm of men, the King called this creature into his presence for the express purpose of learning how to become immortal.

The creature instructed the King to build a transmutation circle in the form of a large trench all around the country, which - when completed and activated - would draw the lives of all Xerxes' people into the center at the palace and grant the King and his court immortality. Despite the abhorrent nature of the ritual, the desperate King agreed and began the long process, willingly sacrificing his loving subjects on the altar of his own ambition. However, when the time finally came for the ritual to go into effect, it became apparent that the King had been tricked by the Homunculus, who had secretly orchestrated the circle so that he and his caretaker alone would stand at the array's true center, thereby receiving the souls of Xerxes' citizens (including those of the royal court) and immortality.

Four centuries later, on the Promised Day, the King is awakened from the whirlpool of souls within Father's body when he "births" a number of humans to prove a point to Van Hohenheim. Finally having returned to a human body after so long, the king mistakenly perceives his rebirth as proof of his desired immortality.

In the manga, unfortunately, as an imitation human, the king's body (as well as the bodies of the other revived Xerxesians) begins to deteriorate rapidly. He is ultimately destroyed when Father unleashes an immense burst of Alchemical energy in an attempt to obliterate the five Human Sacrifices.

Trivia

 * Father's usual outfit is one of the King's royal robes.