TV-Series
Description
Fuyo Kawaguchi, also spelled Fuyuo Kawaguchi, is the eldest of the three Kawaguchi brothers, a trio of mercenaries known collectively as the Machine Gun Brothers in the anime Desert Punk. He is a young man of twenty years with a tall, muscular stature, setting him apart physically from many other characters in the series. His most distinguishing features are the two scars on his face: one horizontal scar running across his nose below his eyes and a vertical scar on his left temple. His typical attire consists of a light brown desert poncho that covers his torso and head, and he wears a white mask, rarely seen without it. While he possesses a sunshade bearing the West Oasis Handyman Guild insignia and the kanji for the number one, he almost never wears it, unlike his younger siblings. His preferred weapon, which he carries slung on his right side, is a formidable M2 Browning.50 caliber machine gun modified with a rifle stock and forward grip.

Fuyo and his brothers, Akio and Haruo, along with their younger sister Natsuko, grew up at Water Station 30, the same home as the series' protagonist, Kanta Mizuno, also known as Desert Punk. During their childhood, Kanta was a troublesome influence, convincing Fuyo and his brothers to engage in petty crimes like stealing from shops and bullying other children. However, this childhood association took a dark turn when Kanta attempted to assault their sister Natsuko. Upon discovering this, Fuyo, alongside Akio and Haruo, beat Kanta severely, establishing a relationship based on animosity rather than friendship from that point forward.

As the oldest brother, Fuyo is fiercely protective of his family, especially his sister Natsuko, and is often seen giving orders to his younger brothers. His motivations are primarily centered on the safety and well-being of his siblings. Always working in tandem with Akio and Haruo, the trio primarily sticks to mercenary work for the West Oasis Handyman Guild. Fuyo’s role in the story often activates when his sister is in danger. On one major occasion, when Natsuko goes missing, he and his brothers are informed by a man named Doronuma and set out to find her, encountering Desert Punk who is on the same mission. Despite their troubled past with Kanta, Fuyo is willing to temporarily team up with him for the sake of finding Natsuko. During the search, he is overpowered and used as a hostage by a powerful cyborg soldier named Nanba, but is later instrumental in the cyborg's defeat, using his heavy machine gun to blast Nanba away after Kanta leads him into a trap.

The story reveals that Natsuko is a member of an anti-government faction. After her brothers rescue her, Fuyo is welcomed into this faction, though this was something Natsuko had secretly hoped to prevent. His loyalty to his sister is absolute, and he later declares he will fight with her to the end, even when confronted by a former ally like Kanta who has switched sides. Fuyo is the only one of the three Kawaguchi brothers who does not appear in any manga chapter by himself, always accompanying his siblings. His primary abilities lie in his immense physical strength, able to carry his heavy machine gun and even grab a large boulder with one hand, and his proficiency with heavy weapons, making him a powerful asset in direct combat. His name, Fuyuo, meaning winter man, reflects the season of his birth, a naming convention he shares with his siblings.