Don Bossman is a sorcerer and the leader of a small group known as the Bravery Quartet. He is a tall, muscular man who appears to be of an advanced age, with a gray beard, small yellow eyes, and a noticeable missing tooth that he has replaced with a gold one. His most distinguishing physical feature is the result of his infection from a Nemesis, which manifests as a pair of small black bat wings and a matching devil-like tail on the back of his otherwise bald head. He typically conceals this infection under a dark brown, pointed wizard's hat. His attire consists of a white, one-piece jumpsuit with thick vertical red stripes. Over this, he wears a red undergarment with yellow stars and a belt, and he completes his look with a red cape, white boots, and several rings and accessories.

At first glance, Don Bossman presents himself as a cheerful, trustworthy, and charismatic individual. He is skilled with words and capable of putting others at ease, often using these qualities to manipulate people and gain their confidence. However, this friendly demeanor is a complete facade for his true nature as a seasoned rogue and con artist. He is a calculating scoundrel who has no qualms about exploiting the suffering of others for personal gain. His cruelty is evident in his willingness to resort to torture to achieve his objectives.

Don Bossman's primary motivation is material wealth and personal survival. He is a pragmatist who sees little value in altruism, especially towards ordinary humans who despise and fear sorcerers. He cynically believes that there is no point in fighting for people who will never be grateful and who persecute those who protect them. This philosophy drives his actions, leading him to use crises as opportunities for theft rather than heroism.

In the story, Don Bossman serves as an early antagonist who challenges the protagonist Seth’s naive and idealistic worldview. He initially appears to be a helpful and inspiring fellow sorcerer, offering guidance and encouragement to Seth during a Nemesis attack. He entrusts Seth with the task of holding off the monster while his group evacuates the townspeople. In reality, this is a ruse; the Bravery Quartet uses the chaos to rob the local bank. When Seth discovers the betrayal, Bossman tries to justify his actions by arguing that sorcerers will never be accepted by society, and that Seth is a fool for risking his life for those who hate him. He attempts to recruit Seth to his way of thinking, suggesting that sorcerers should only fight for themselves.

His key relationship is with Seth, whom he sees as a naive but useful tool. He is the leader of the Bravery Quartet and commands the loyalty of his crew, who assist him in his schemes.

Throughout his limited appearance, Don Bossman shows little personal development, remaining steadfast in his cynical beliefs. However, his role is crucial for the development of the protagonist. His betrayal and harsh truths force Seth to confront the harsh reality of how sorcerers are treated, acting as a catalyst for Seth’s determination to prove that a different path is possible.

As a sorcerer, Don Bossman is capable of using Fantasia, the magic of his world. While his specific offensive abilities are not the focus, he demonstrates considerable skill. He and his team are able to use a spell powerful enough to temporarily seal a large Nemesis. He also shows a degree of cunning and resourcefulness, such as devising a way to create undergarments from feathers so he could still use his magic even when otherwise unclothed.