Chosan is an investigator from the Witch World who serves as a recurring antagonist in the story. His official mission is to observe and report on the two candidates competing for the throne of the Witch World, but he is far from an impartial judge.

Standing out with his distinctive grayish skin, Chosan is typically portrayed as a short, scheming man with a comical appearance, often including a pair of prominent front teeth that resemble shovels. His name itself is a pun on the Japanese word for examiner, highlighting his assigned role even as he subverts it for his own purposes.

Chosan is fundamentally a cowardly, lecherous, and petty individual who delights in causing trouble for the main protagonist. His personality is defined by a deep-seated perversion and a knack for voyeurism, as he frequently spends his time spying on the young witch candidates, hoping to catch them in embarrassing or compromising situations. He is the quintessential dirty old man, and his plots are almost always designed to publicly humiliate the heroines, with a particular focus on schemes of a salacious nature. For example, he once rigged a bathtub with wheels to send it racing through the city while the occupant was bathing, and on another occasion, he attempted to use a hypnotic magical clock to trick a character into removing all her clothes. Despite his malicious intent, Chosan is also a notorious coward and a consistent failure. His plans are perpetually foiled, and he inevitably ends up as the victim of violent and humiliating comeuppance, serving as the story's primary chew toy and butt-monkey.

While he pretends to act on behalf of the Witch Queen, Chosan secretly serves a darker master. He is later revealed to be a henchman, or the dragon, for Saturn, the Queen of Darkness, and actively works to sabotage the chances of one candidate while secretly favoring the other to serve Saturn's agenda. This duplicity forms the core of his role in the story, as he is not merely an incompetent nuisance but an agent of genuine antagonism sent to interfere with the royal selection process. He is a constant source of conflict for the protagonists, forcing them to deal with his magical traps, surveillance, and manipulations on top of their other challenges.

Despite being a villain, Chosan rarely works alone. He is almost always accompanied by his two loyal, though equally disliked, animal sidekicks: a cat named Furu Furu and a crow named Kuro. This trio is universally disliked, with Chosan himself being hated by all other animals, who seem to instinctively recognize his unpleasant nature. His relationships with the main characters are purely antagonistic. He holds a particular disdain for the main protagonist and revels in her hardships, though this animosity is largely driven by his own perverse pleasures and his allegiance to Saturn rather than any personal grudge.

Chosan shows no meaningful character development or redeeming arc throughout the series. He remains a static figure of incompetence and malice from his first appearance to his last. In the final episode, his treachery is formally addressed when he is captured and punished by the Witch Queen for his actions, assigning him to menial labor as a cleaner in the royal palace as penance for his crimes.

Despite his lack of magical power compared to the witch candidates, Chosan possesses several notable abilities. He is a skilled inventor of magical contraptions and gadgets, such as the wheel-equipped bathtub and an invisibility cloak he used to harass the heroines. He also has the means to communicate with and serve the Dark Queen Saturn. However, his most persistent ability is perhaps his talent for surveillance and infiltration, as he is constantly seen lurking and spying from his tower or climbing walls, even if he is almost always caught and punished for his efforts.