Joseph is a central character from the series, serving as a young soldier during the Hundred Years' War. He is a peasant serving under a lord named Guillaume, and his role in the story begins when he encounters Maria, a powerful witch, and becomes infatuated with her ideals and her dream of peace. His background is one defined by constant conflict, as he explains that he has never known a time without war, a reality that allows him to sympathize deeply with Maria's pacifistic views. Physically, Joseph is depicted as a tall young man with straight red hair and green eyes.

In terms of personality, Joseph is initially characterized as a meek and kind individual who often suffers from low self-esteem. He is described as being a very good person, with strong morals and a deep sense of empathy, sometimes to the point of being easily taken advantage of by others. Despite coming across as cowardly or submissive due to his gentle nature, he possesses significant hidden courage. This bravery is most evident when he stands up to the archangel Michael, armed with nothing but a crossbow, to defend Maria, an act that ultimately leads to God giving her a second chance. He is also noted to be a virgin, a trait that aligns him with Maria in a story where virginity is directly tied to magical power.

Joseph's primary motivation is his love for Maria and his support for her cause. He believes in the spirit of God's law rather than the strict interpretation of the church or heaven, and he is willing to risk his own safety to protect her and her mission to stop bloodshed. He is not above begging or humbling himself, such as when he pleads with the priest Bernard not to harm Maria. His actions are driven by a desire to serve and protect, caught between his duty as a soldier and his loyalty to the witch.

Within the story, Joseph serves as the male lead and the primary human connection for Maria. His declaration of love for her in front of the archangel Michael is a pivotal moment that changes her fate, shifting her punishment from immediate execution to a trial where her powers depend on her virginity. He acts as a moral anchor for Maria, and their relationship forms the emotional core of the narrative. The dynamic between them inverts typical gender roles, with Joseph often taking on the role of the supportive, emotionally intelligent partner while still holding his own as a capable individual. They are portrayed as equals who complement each other's flaws; he helps her maintain confidence, while she helps him become less of a pushover.

Joseph also has significant relationships with other characters, most notably the mercenary Galfa. Formerly friends, their relationship sours dramatically after Galfa attempts to assault Maria. This event triggers a fierce, vengeful side of Joseph, who tracks down Galfa and brutally beats him, an act he immediately regrets, believing it makes him unworthy of Maria. This relationship highlights the internal conflict between his inherent kindness and his capacity for righteous fury. He also interacts with the angel Ezekiel and the priest Bernard, often serving as a humble counterpoint to their rigid authority.

Throughout the series, Joseph undergoes notable development. He transitions from a meek soldier with low self-esteem to a more confident and brave individual. His willingness to stand up to divine and earthly authorities grows, and he learns to reconcile his gentle nature with the harsh realities of his world. His relationship with Maria matures, culminating in a love confession that not only solidifies their bond but also helps Maria regain her lost magical powers. As a human with no supernatural abilities, Joseph's primary strengths are his unwavering loyalty, his moral conviction, and his courage. He is an ordinary man whose extraordinary faith in love and goodness allows him to influence the course of events involving angels and witches.