Bakunetsumaru, also known as the Blazing Samurai, is a samurai Gundam from the nation of Ark. His origin lies in a devastating civil war within his homeland, where he served his master, the daishogun Bururitenmaru, in a struggle against the forces of the warlord Kibaomaru, who later allied with the dimensional invaders known as the Dark Axis. During a battle involving a dimensional transport device, Bakunetsumaru and his loyal steed, Entengo (also known as the Flame Heavenly Horse), were accidentally transported away from Ark and crash-landed in the futuristic city of Neotopia.

In terms of personality, Bakunetsumaru is a quintessential hot-blooded warrior, characterized by his strong sense of honor, straightforwardness, and fierce loyalty. He is deeply passionate and prone to dramatic emotional outbursts, often leading to comedic clashes with more reserved characters. Despite his courage in battle, he possesses several notable fears, including a terror of heights and a profound fear of ghosts, which provides much of the series' humor. He also has a simple and belligerent side, frequently arguing with his teammate Zero due to their contrasting personalities, yet this conceals a deep-seated sense of camaraderie and fellowship. Bakunetsumaru is also known for his love of rice balls, a traditional food of samurai from Ark.

Bakunetsumaru's primary motivation throughout the story is twofold. Initially, his driving goal is to find a way back to his war-torn homeland of Ark to continue the fight and redeem himself in the eyes of his master. However, after witnessing the Dark Axis's threat extend into Neotopia, he also becomes fiercely dedicated to protecting his new home and allies. He is deeply troubled by the civil war destroying Ark and carries the weight of his duty to correct the disordered world. His sense of honor is paramount, and he is driven to prove his loyalty and worth as a warrior, especially after being falsely accused of cowardice.

Within the story, Bakunetsumaru serves as a core member of the titular Gundam Force, representing the samurai archetype from the world of Ark. His role is that of a powerful frontline fighter whose raw power and martial skill are indispensable in battle. His arrival in Neotopia marks a turning point, and he officially joins the Super Dimensional Guard after being impressed by their fight to protect others. He often acts as a foil to the knightly Zero, with their bickering masking a mutual respect. His personal journey is central to the second half of the series, which sees him return to Ark to confront his past, clear his name, and ultimately help end the civil war.

Key relationships define much of his character arc. His bond with his master, Bururitenmaru, is one of deep loyalty and a desperate need for approval, making the accusation of treason devastating. He shares a fierce rivalry with Kujakumaru, a former friend and fellow student who, after being defeated and then spared by Bakunetsumaru, defected to Kibaomaru out of shame and renamed himself Ashuramaru. His friendship with his Gundam Force teammates, particularly Captain Gundam and the knight Zero, is crucial, as they help him adapt to a new world and support him in his personal quest. He also forms a significant bond with the young human Shute, whose courage often inspires the Gundam Force. Later, he takes on a mentor-like role for the young samurai Genkimaru.

Bakunetsumaru undergoes significant development. He starts as a warrior obsessed with returning home, but grows to accept his role as a protector of multiple worlds. His most profound development occurs when he returns to Ark and is branded a traitor. After being mortally wounded while protecting his master, his unwavering loyalty and resolve cause the legendary Bakushin Armor to choose him. This transformation into Bakushinmaru, also known as the Reinforced Sword Ram Bakushinmaru, is a pivotal moment. The armor, powered by the wearer's life force and spirit, heals his wounds and grants him immense power, but its use is mentally taxing. This evolution represents him mastering his inner turmoil and proving his noble heart, finally regaining his master's trust and fulfilling his destiny. By the story's conclusion, after the final defeat of General Zeong, he remains in Ark to help rebuild his homeland with Genkimaru, seeing off his friends as the Gundam Force disbands.

As a warrior, Bakunetsumaru is defined by his notable abilities. He is a master dual swordsman, fighting with two katanas; his right-hand sword is specifically identified as one of the Five Sacred Swords of Ark. His signature technique is the Bakunetsu Tenkyoken, a devastating special move where he unleashes a massive, flaming X-shaped energy blast with his blades. In his empowered Bakushinmaru form, he gains access to even more destructive techniques, such as the Baku Kaitensho, which allows him to burn everything around him by exploding the energy of his armor. He is also often accompanied by his steed, Entengo, a rottweiler-like mechanical horse with a unique cry.