Fullmetal Alchemist: Brotherhood is a fantasy shonen series renowned for its deep, complex plot as well as its combat system, based on arcane transmutation circles and symbology. Many of the most powerful characters, including protagonist Edward Elric, use alchemy in combat, and even the villainous homunculi use it via their Philosopher's Stones.
However, the story makes it clear that alchemy really isn't everything. Some characters misuse it or let it get to their head, such as when Shou Tucker created a chimera out of his daughter or when Colonel Roy Mustang almost went to the dark side with his quest for revenge. Meanwhile, these five Fullmetal Alchemist characters stand out even without the gift of alchemy, and they all impact the plot and its many action scenes.
Lieutenant Riza Hawkeye, Roy Mustang's Better Half
Lieutenant Riza Hawkeye was introduced as an expert sharpshooter/sniper and Roy Mustang's loyal friend in the Amestris military. She has no fear on the battlefield -- even when cornered by the all-devouring Gluttony -- and she survived the Ishval Civil War by detaching herself from the slaughter with long-range shooting.
Now she's facing great perils to help Roy and Edward Elric take on the corruption in the Amestris military, and preserve peace and justice for all people. Riza is also Roy's conscience when he needs it, helping him avoid losing himself to hatred in the process of destroying Envy. She can't perform a single bit of alchemy, but Roy wouldn't get anywhere without her.
Major-General Olivier Armstrong, The Name & Face Of Fort Briggs
The great northern fortress of Briggs is the sole bulwark defending Amestris from the massive nation of Drachma, and Major-General Olivier Armstrong is the heart and soul of that steel wall. Olivier made a strong first impression with her tough words and pragmatic philosophies, and she can keep entire armies at bay with her reputation alone -- no alchemy required. She's an exemplary commander and a sly rebel when the situation calls for it, even training her men to keep up the good work when she's not around.
Olivier also got her share of awe-inspiring scenes, such as when she used a battle tank indoors to fight off Sloth the homunculus, or when she slew the scheming General Raven and deposited his body in wet concrete. No one crosses Olivier Armstrong and lives.
Maes Hughes, An Intelligence Agent
Although Maes Hughes only appeared in Fullmetal Alchemist: Brotherhood for a short time before dying at the hands of Lust and Envy, he made a strong impression and set a high standard for all Amestris soldiers and agents. Maes was well-liked and had powerful charisma, and his survival of the Ishval Civil War made it clear that his skills as a soldier were advanced. He also added a much-needed ray of light to the story with his intense love for his wife and young daughter.
Most remarkable of all was Maes' early and insightful investigation into Father's true plans, piecing the puzzle together before anyone else. Unfortunately, that's what got him killed -- Lust and Envy needed to shut him up to protect Father's plans.
Captain Buccaneer, Who Bravely Faced Wrath In Battle
One of Olivier Armstrong's most notable soldiers is Captain Buccaneer, who gave Edward and Alphonse Elric a rough welcome when they approached Fort Briggs in the middle of a blizzard. Buccaneer is a great bear of a man with an automail right arm, taking part in the final battle for Central and facing the powerful homunculus Wrath with no fear at all. He couldn't defeat Wrath alone, but with the help of Fu and Greed/Ling he delivered a mortal blow to Wrath before succumbing to his own injuries. In the end, Captain Buccaneer's efforts helped Scar the monk defeat Wrath a bit later.
Lan Fan, Prince Ling's Top Bodyguard
The people of the faraway Xing sometimes practice alkahestry, a healing art that May Chang is known for utilizing. Most other assassins and warriors from Xing don't have the benefit of alchemy, though, so they make do with weapons and martial arts. Prince Ling Yao's bodyguards, Fu and Lan Fan, can stand up to any alchemist or even a homunculus in battle with no alchemy of their own. Lan Fan once severed her own arm to escape Wrath and Gluttony, and throw the latter off her scent.
Later in Fullmetal Alchemist, Lan Fan got herself an automail arm with Winry's help and saved Ling's life against Wrath. She was a star during the forest battle against Pride and Gluttony, using her extreme speed and blades to repeatedly kill Gluttony and put Pride's team on the back foot. She even used flash-bang grenades to negate Pride's shadow-based powers. Not bad for a non-alchemy user.