Artemis is a central figure in the story as the familiar and self-proclaimed servant of the young witch Maria. She is a succubus, a type of demon, whom Maria created by magically transforming an owl. This origin is reflected in her ability to shift between two primary forms: that of a striking woman with long, pale blonde hair and pink eyes, and a smaller, pink-hued owl.

In her human guise, Artemis embodies the characteristics of a succubus. She is highly seductive and possesses a confident, often forward personality. She enjoys her role and takes pride in her work, which involves using her charms to manipulate others, particularly the soldiers involved in the Hundred Years' War. Artemis has a playful and teasing nature, and she frequently uses her knowledge of carnal matters to embarrass Maria, who is famously naive about sex. Her frank and shameless comments often serve as a source of comedic relief, contrasting sharply with Maria's more serious and idealistic demeanor.

Despite her teasing and the inherent hierarchy of a witch and her familiar, Artemis is profoundly loyal to Maria. She does not view their relationship as one of master and servant, but rather as a close friendship. This deep-seated care drives her to put herself in significant danger, including standing up to the Archangel Michael, in order to protect her mistress from threats posed by both humans and heavenly beings.

Artemis's primary function in the story is to assist Maria in her goal of stopping the bloodshed of the war. While Maria prefers to use grand magic to halt battles, she sends Artemis on nightly missions to achieve a similar effect through different means. Artemis visits the camps of enemy commanders and soldiers, using her seductive abilities to sap their energy and morale, thereby making them less inclined or able to fight. This tactic is presented as a pragmatic, if unconventional, method of pacification. She is also fiercely protective of her own freedom and the life Maria gave her, and she does not hesitate to voice her opinions, often scolding or bossing Maria when she feels it is necessary.

Her relationships extend beyond Maria. She shares a dynamic with the other familiar, Priapos, an incubus also created from an owl. Together, they display traits of their animal origins, often acting like birds of prey. This is most evident in their shared tendency to antagonize the angel Ezekiel, who takes the form of a dove, justifying their behavior by their nature as predators. Artemis often finds Ezekiel's rigid, pure worldview to be annoyingly narrow-minded, championing the idea that the world is sustained by a balance of both purity and profanity. Throughout the series, Artemis's development is less about a fundamental change in character and more about the deepening of her loyalty and her role as Maria's steadfast companion, willing to face any adversary by her side.