Michael Gallet, whose name is sometimes rendered as Michael Garret, is a central figure in the narrative of GUNxSWORD. He is the older brother of Wendy Garret and, following the death of their parents, was her only remaining family in the town of Evergreen. In his youth he was protective and caring toward Wendy, notably defending her from bandits who attacked their town. This early bond is the foundation of his character arc.

His life changes when he is kidnapped from Evergreen by the Claw, the series' main antagonist. However, rather than remaining a captive, Gallet comes to willingly join the Claw's cause. The Claw envisions the eradication of all sorrow by creating a new world, and Gallet becomes a devoted follower, believing in this ideal. He is recruited as a member of the Original Seven, a group of elite pilots, because he possesses the rare ability to control an Original Armor without needing surgical implants. This natural compatibility makes him a key asset in the Claw's plan. He pilots the armor Saudade of Sunday, a machine that resembles an enormous energy handgun.

In terms of personality, Gallet is generally kind and compassionate, much like his sister, but he also displays a fierce independence. Despite his voluntary alignment with the Claw, he harbors internal doubts and struggles with the morality of the project, especially when a mutinous group tries to sway him. Ultimately, he chooses to remain loyal to the Claw and to Fasalina, another loyalist with whom he forms a deep romantic bond.

His role in the story is multifaceted. Initially, he is the goal of Wendy's journey; she joins Van to rescue him. When they finally meet, Gallet reveals his voluntary allegiance, which shocks Wendy and forces her to reassess her own mission. From that point, he becomes an antagonist to Van and his companions. He engages Van in aerial combat using Saudade of Sunday, and their battle is marked by Van's relentless taunts about Gallet's neglect of his sister. This enrages Gallet, who blames Van for taking Wendy away from Evergreen. The fight ends with Gallet's defeat and the destruction of his armor.

Gallet's development culminates in an emotionally charged encounter with Wendy in the penultimate episode. When he insists on continuing his mission, Wendy uses the last bullet of his own gun to shoot him in the arm. She argues against the Claw's plan, and although Gallet initially reacts with fury, he ultimately saves her from falling debris. In that moment, the siblings reach an understanding. Gallet gives Wendy his gun and tells her to follow her own path while he follows his. He then rushes back to save Fasalina; the two are last seen together as a boulder falls upon them, with their fate left ambiguous.

Among his notable abilities, Gallet is a skilled pilot of the Original Armor Saudade of Sunday, which he controls through his natural aptitude. He is also shown to be capable in hand-to-hand combat and marksmanship, though his primary strength lies in his mecha. His internal conflict—between his love for his sister and his commitment to the Claw's dream—drives much of his character development. By the series' end, he reaffirms his bond with Wendy while still choosing to stand by his own convictions, accepting whatever consequences may come.