Artemisa, often referred to by the more common spelling Artemis, is a white, male, talking cat who serves as a trusted guide and advisor to Minako Aino, the Sailor Guardian known as Sailor Venus. His origins trace back to the time of the Silver Millennium, where he and his partner Luna served as advisors to Queen Serenity. When the Moon Kingdom was destroyed, Queen Serenity sent them forward in time to Earth's future to awaken and guide the Sailor Guardians. Artemisa was instrumental in awakening Minako's powers as Sailor V, a role he fulfilled long before Luna found the other Guardians. He is characterized by a calm, patient, and easygoing personality, which stands in contrast to Luna's more serious and often stricter demeanor. Artemisa is friendly, courageous, and notably more relaxed, often tolerating Minako's eccentric and occasionally irresponsible behavior with good-natured patience, even when she treats him roughly or locks him away. He is highly devoted to Minako, acting as a protector and a source of unwavering support, always ready to encourage her or bring her small gifts like flowers to lift her spirits.

Within the Sailor Moon SuperS arc, Artemisa's role is significantly defined by his relationships and the evolution of his personal story. His primary motivation remains the protection of Earth and the success of the Sailor Guardians in their mission, but he is also deeply driven by his care for Minako and his growing romantic feelings for Luna. During this season, a key development occurs with the arrival of Diana, a small pink kitten from the future. Diana is revealed to be the future daughter of Artemisa and Luna. This appearance initially causes a misunderstanding, as it is believed that Diana is solely Artemisa's child, which triggers jealousy in Luna and inadvertently reveals her own romantic interest in him. Once this confusion is resolved, Artemisa is overjoyed to learn that his love for Luna is reciprocated and that they are destined to start a family, bringing him great happiness and solidifying their future together. Throughout the series, including SuperS, Artemisa is highly skilled with computers and technology, often using his abilities to gather information or assist the team from their command center. While his powers are not primarily combat-oriented, his wisdom, strategic thinking, and role as a mentor are invaluable to the team, providing guidance and the means for the Sailor Guardians to power up when necessary.