Daimon is a central character in the anime Samurai Gun, operating as a member of the clandestine vigilante group known as the Samurai Gun. His public identity is that of a teacher, a profession he maintains during the day as a cover for his covert activities. By night, he partners with his close associate Ichimatsu on various missions aimed at opposing the corrupt Shogunate and its brutal enforcers.

Personality-wise, Daimon is portrayed as pragmatic and committed to the cause of justice that defines the Samurai Gun organization. He takes an active role in recruiting Ichimatsu for their operations, consistently urging him to take up his gun to fight against oppression. Unlike Ichimatsu, who is frequently reluctant and weary of the endless cycle of violence, Daimon holds a firmer belief that their actions exist on a different moral plane, representing justice rather than mere vengeance. He argues that what they do is fundamentally different from the cruelty of their enemies. Despite his serious dedication to the mission, Daimon also displays a subtle, wry sense of humor, as evidenced by a moment when he jokes about his collection of pornography, telling Ichimatsu that he can have it if he does not return from a dangerous assignment.

Daimon's primary motivation for becoming a Samurai Gun stems from a personal history of standing up against injustice. He was once arrested for doing what he believed was right and was sentenced to commit seppuku, a sentence he ultimately could not carry out. This experience, while not detailed extensively, solidified his resolve and his reliance on his comrades. In the story, his role is that of a fellow operative and a key mission coordinator. He frequently brings mission briefings to Ichimatsu at the tavern where Ichimatsu works, acting as the catalyst that pulls the reluctant protagonist back into action. His role is not solely as a fighter; he also gathers intelligence and works alongside other members of their organization.

Key relationships are central to Daimon's function in the narrative. His bond with Ichimatsu is the most significant, built on mutual trust and shared peril. There is a notable scene where Daimon, expecting to die, leaves behind maps and information for Ichimatsu, trusting that his partner will come to his aid if needed. This trust is reciprocated when Ichimatsu and Kurenai mount a rescue mission to save Daimon from enemy captivity and torture. Their teamwork is a consistent element of the plot, with Daimon often providing backup or tactical support. He also works alongside fellow operative Kurenai, the singer at the tavern, forming a core team of three that handles the most critical assignments.

Daimon undergoes some development through the trials he faces. A significant moment is his solo mission to retrieve secret documents, during which he is captured and tortured. In this ordeal, his captor, the antagonist Watou, notes that the fact Daimon has not committed suicide means he is confident his comrades will save him. This demonstrates a deep-seated trust and reliance on his team, moving him from a solitary fighter to a man who understands the value of his bonds. His survival and rescue reinforce the theme of unity against a common foe. As a teacher, he also serves as a contrast to Ichimatsu, grounding him in a form of normal life outside of violence.

In terms of abilities, Daimon is a competent combatant, skilled enough to serve as a front-line member of an elite black-ops force. While the series focuses more on Ichimatsu's gunfighting, Daimon proves his capability in infiltration and direct confrontation, holding his own against enemy forces to allow his teammates to escape. His skills also extend to intelligence gathering and planning, making him a well-rounded operative beyond just his prowess with a firearm. His daytime cover as a teacher also suggests a level of discipline and the ability to maintain a dual life under the scrutiny of a repressive regime, which requires as much mental fortitude as physical skill.