Maes Hughes is a fictional character from the Fullmetal Alchemist universe, serving as an officer in the Amestrian State Military. Initially introduced with the rank of Major in one anime adaptation, his more consistent rank across the manga and other adaptations is Lieutenant Colonel, where he is placed in charge of the Investigations Division in Central City. A veteran of the devastating Ishval Civil War, Hughes fought not as a State Alchemist but as a regular soldier, an experience that deeply changed his perspective alongside his close friend, Roy Mustang. Before the war, Hughes had known Mustang since their days at the military academy, and it was Hughes who introduced Mustang to a young Riza Hawkeye, the sniper who would become Mustang's trusted subordinate.

On the surface, Maes Hughes presents a jovial, friendly, and almost comically eccentric personality. He is famously and unashamedly devoted to his family, consisting of his wife, Gracia, and his young daughter, Elysia. This devotion manifests in his most well-known habit: constantly showing photographs of his daughter to colleagues and friends, often to their great annoyance, while enthusiastically praising her. This behavior, while played for humor, is understood to be a deliberate coping mechanism, a cheerful shield that protects himself and others from the often dark and depressing nature of his investigative work. Beneath this goofy exterior lies a markedly different person: a shrewd, highly intelligent, and deeply serious military officer. He is a realist and an exceptional analyst with a keen eye for detail, capable of remaining calm and making sharp tactical decisions even under immense pressure. His kindness extends to mentoring younger characters like Edward and Alphonse Elric, offering them hospitality and sage advice, and even taking in the bookish Sheska as his assistant.

Hughes's primary motivation is twofold. On a personal level, his happiness is completely wrapped up in the safety and well-being of his wife and daughter. Professionally and politically, his driving goal is to support his best friend, Roy Mustang, in his secret ambition to become the Führer of Amestris. Having witnessed the horrors of the Ishval Civil War, both men became critical of their country's direction, and Hughes believes that by helping Mustang rise to the top, they can create meaningful change. He famously pledges to "work below him and help push him to the top". This commitment makes him an invaluable, if unofficial, ally and intelligence source for Mustang, who is stationed in the distant East Area.

As a member of the Investigations Division, Hughes's role in the story is often that of an information broker and supporter rather than a front-line combatant. However, when drawn into action, he demonstrates notable abilities. Despite being unable to use alchemy, he is a highly skilled knife-fighter, specializing in the use of small push knives or throwing blades which he keeps concealed on his person. His skill is considerable enough to injure Lust, a powerful homunculus, by throwing a knife directly into her forehead. More significantly, his greatest ability is his sharp intellect and investigative prowess. Using only drawings from Edward Elric of what he witnessed in Laboratory 5, Hughes is able to conduct research and deduce the military's secret plan to create a nationwide transmutation circle, a conspiracy at the very heart of the story's conflict. It is this discovery that seals his fate. While attempting to contact Mustang from a public phone booth to relay this crucial information, he is confronted by Envy, a homunculus capable of shapeshifting. Recognizing the disguised Envy, Hughes manages to wound him, but Envy transforms into the form of Hughes's beloved wife, Gracia. This moment of hesitation is fatal, and Envy shoots and kills him. In the wake of his death, Hughes is posthumously promoted two ranks to Brigadier General, a gesture that does little to console his grieving friends and family. His loss serves as a profound and traumatic turning point, becoming a core motivation for Roy Mustang's subsequent quest for vengeance and justice.