Artemis, also known as Arte, is a character who appears in the second half of the anime Tsukuyomi: Moon Phase. She is introduced as a vampire with a physical appearance that marks her as younger than the protagonist, Hazuki. Artemis has long pink hair and pink eyes, which are noted to turn red during a full moon. Her attire often includes a dress and a bow, contributing to a childlike visual design that contrasts with the more serious nature of her actions.

As a character, Artemis is defined by a deep-seated envy and resentment toward her older sister, Hazuki. Born to a different mother, she perceives that the family dedicates all its attention and affection to Hazuki, leaving her feeling neglected and overlooked. This jealousy festers into a central motivation: to deprive Hazuki of everything and everyone she truly cares for. Artemis is determined to take by force or destroy completely any person or thing that brings her sister happiness. This antagonistic drive positions her as a significant obstacle within the story, a personal foe whose grudge is intimately tied to Hazuki's past.

Within the narrative, Artemis serves as a foil to Hazuki, embodying the destructive potential of loneliness and familial rejection. Her role is not merely that of a villain but also a tragic figure shaped by the circumstances of her upbringing. Her key relationships are primarily defined by this familial bond. She acts under the guidance of a guardian named Vargus, whose influence reinforces her negative behavior. Her interactions with the male lead, Kouhei Morioka, become crucial to her character arc. Unlike the hostile relationship she seeks with her sister, Kouhei is able to reach out to her. In the series finale, following the death of Vargus, Artemis is taken into the Morioka family. Kouhei’s patience and care convince her to open up to a new life surrounded by caring friends and family, marking a significant shift away from her previously destructive goals.

Artemis possesses notable abilities tied to the manipulation of shadows. She is a shadow user, meaning she can extend and shape her own shadow into physical forms. Her primary combat application of this power is to form the shadow into a large, sharp scythe for use as a weapon. Additionally, she can use her shadow to create a replica of herself, a technique that allows for deception or distraction in a confrontation. These abilities make her a formidable opponent, despite her small stature. In the manga source material, the details of her situation differ slightly; there, she is forcefully rejected by her father and subsequently taken into the care of Kouhei's father to act as a replacement in Hazuki's absence, further emphasizing her role as a figure displaced from her own family.