Halcrow/Overview

Major General Halcrow (also spelled "Hakuro") is a State Military Officer stationed in the bustling city of New Optain in the Eastern Area of Amestris.

Though significantly endowed with military power, he is below Lt. General Grumman in the echelon and, therefore, cannot take action in regards to his open disapproval of Roy Mustang's speedy rise through the ranks under Grumman's command. Frustrated and threatened by Colonel Mustang's notoriety, Halcrow is known to make multiple attempts to bully or belittle the Flame Alchemist, all of which end up fruitless.

His Part in the Story
He first appears in Chapter 4, when the train on which he and his family ride to a vacation spot is hijacked by Bald and several members of the Blue Squad, seeking to hold the Major General ransom in exchange for their incarcerated leader. While attempting to discourage the terrorists, the general is lightly wounded as Bald shoots a small hole in his left ear. Before any more harm can come to the Halcrow family, however, the hijackers are defeated by Edward and Alphonse Elric, who also happened to be passengers aboard the train.

Halcrow reappears after the initial battle with Scar, coming down to East City from New Optain to berate Mustang for taking so long to find the alchemist murderer, and again in Chapter 85 to inform Führer Bradley of Mustang's attempted coup d'etat in Central City. However, it becomes apparent that Halcrow's report was included in Mustang and Grumman's plans without his knowledge, as they used him as bait to draw Bradley into an assassination trap.

2003 adaptation
In the 2003 anime series, Halcrow's rescue by the Elric brothers was partly orchestrated by Mustang in order to manipulate the Major General into exempting the boys from the age restriction for the State Alchemy exam. After the Elrics' mission in Reole, Halcrow is assigned to liberate it from Cornello's followers and his actions create political unrest due to the manipulative actions of the Homunculi and he also ignores Rosé's advice about allowing the citizens to fix the town themselves and leaves her to be tortured and eventually raped and impregnated with a child. Halcrow later attempts to seize the presidency for himself while King Bradley is temporarily indisposed.

Near the end of the series, Halcrow is assigned to the mission of hunting down the Elric Brothers - who have gone away without leave - and is determined to do it as he is embarrassed due to the Elrics using him to get into the military. Halcrow is later sent to deal with Brigadier General Mustang and his uprising against the Führer in Drachma, unaware that this is a diversion to lure the bulk of the military forces away from Central Command.

Fullmetal Alchemist (movie)
In the 2017 film, Halcrow is potrayed as far more sinister and demented, and is working with the Homunculi to  create Mannequin Soldiers for them. He is implied to have hired Shou Tucker to create them with Alphonse's Transmutation Circle after he finishes his second human chimera, but in order to do so he separates the Elric brothers and later stages the death of Maes Hughes and Tucker's arrest, so that he can create the Mannequin Soldiers with the Homunculi. In the final showdown, he foolishly awakens the Mannequin Soldiers and later declares he is their "daddy" but they turn on him and later eat him alive. His death is akin to the general who dies in Chapter 90: Army of Immortals.

Trivia

 * Ear.pngugh Halcrow was shot in the ear during the train incident in the fifth episode of the 2003 anime, the ear wound is not seen in all of Halcrow's subsequent appearances.
 * Halcrow's role in the 2009 anime is greatly diminished to that of a one-time background character.
 * It's possible that Hakuro's given name began as a mis-transliteration on the part of the author, who intended to name him "Halcrow".