Live action TV
Description
Father Cornello is the self-proclaimed Messenger of God and the charismatic founder of the Church of Leto, a religion he established in the small desert town of Reole in Eastern Amestris. Before the Elric brothers arrive, Cornello has successfully built a devoted following by performing what the townspeople believe to be divine miracles, effectively creating a theocratic government with himself as the unquestioned ruler.

Outwardly, Cornello presents himself as a paternal and benevolent figure, speaking kindly and providing reassurances to his followers in the name of the sun god Leto. He takes advantage of the desperation and hopes of the people, promising them happiness and even the resurrection of deceased loved ones. However, this gentle facade masks a truly corrupt and power-hungry nature. In reality, Cornello is spineless, greedy, and ruthless, viewing his congregation not as people to be cared for but as mindless pawns and fools to be exploited for his own grand ambitions. He has no qualms about killing those who get in his way or become disloyal, demonstrating a complete lack of regard for human life, even attempting to have his most faithful follower, a young woman named Rose Thomas, killed when she befriends the Elric brothers.

Cornello's primary motivation is purely self-serving. He confesses that his plan is to create a massive army of religious fanatics, a legion driven by a holy call, which he will use to overthrow the Amestrian government and install himself as the ruler of the entire country. He relies entirely on a ring set with a Philosopher's Stone to perform his miracles, which are in fact acts of alchemy that appear to break the fundamental law of equivalent exchange. When the Elric brothers, Edward and Alphonse, arrive in Reole and see through his deception, he becomes a direct antagonist to them. He is deeply suspicious of Edward, a State Alchemist, fearing that the boy will expose his fraud. His relationship with Rose Thomas is one of exploitative manipulation; he preys on her grief over her lost fiancé to ensure her loyalty, promising to bring her loved one back. Unbeknownst to Cornello, his power is entirely contingent on the homunculi, specifically Lust, who gave him the fake Philosopher's Stone as part of a larger scheme. He is a mere pawn in their game.

In terms of character development, Cornello experiences a dramatic fall from power rather than personal growth. When Edward Elric exposes his plot over the church's own radio, Cornello's control over the town instantly crumbles. Desperate, he attempts to use the Philosopher's Stone to unleash greater power, but the stone is revealed to be an imitation, causing an alchemical rebound that deforms his arm, horrifically melding it with the weapon he had created. After his defeat, he flees to confront Lust, the homunculus who gave him the stone, demanding answers. Finding that he has outlived his usefulness as a pawn, Lust callously kills him, and his body is devoured by Gluttony. In a final act of manipulation, the shapeshifting homunculus Envy then assumes Cornello's form to further destabilize the town, proving that even his identity is ultimately disposable to the forces that empowered him. While the outcome remains the same in all versions, the 2009 anime adaptation of Fullmetal Alchemist: Brotherhood shows him briefly using the stone's power to morph into a gigantic, monstrous version of himself before being defeated, whereas in the original 2003 anime and manga, he is rendered practically useless immediately after the rebound.

Father Cornello's notable abilities are entirely derived from the false Philosopher's Stone in his ring. Using the stone, he can perform alchemy without a transmutation circle and appears to bypass the Law of Equivalent Exchange, creating matter from nothing in the eyes of the townspeople. He uses this power to perform flashy public miracles, create chimeras to serve as his guards, and even generate a massive cannon to use against the Elric brothers. Without the stone, however, Cornello possesses no alchemical power of his own, revealing him to be a powerless fraud and a coward who relied entirely on an external artifact for his status and influence.