Maeve Hoshisato, born into the Grene family known for their rare power to craft magical Artifacts, possesses the Crafter ability to imbue objects with power through love during their creation. Rejecting her family's path of commercializing Artifacts for wealthy clients, she departed her homeland for Japan after falling in love with Mamoru Hoshisato, a non-magical stage magician. This marriage created a lasting rift with her original family.

She and Mamoru raised two daughters, Kana and Yumemi Hoshisato. To counter the misuse of Artifacts scattered worldwide, Maeve adopted the secret identity "Thief Maeve." Combining her magic with Mamoru's stage illusions, she embarked on global missions to retrieve these potent items, directly opposing her family and their profiting allies.

Maeve entrusted her daughter Kana with a significant Artifact: the magical scarf Muff, symbolizing her hope that Kana would carry on her mission. She also gave a magic wand Artifact to Makoto Shiranui, her daughters' childhood friend, though the precise timing is unclear. Maeve's current whereabouts are unknown, and her disappearance motivates her family. Her younger sister, Mariah Grene, later surfaced under family orders to reclaim Artifacts, confirming Maeve's original surname and the enduring conflict.

Maeve has long blond hair and blue eyes. She typically wears an eggplant-colored pointed hat bearing a gold heart emblem, a navy cape with a scarlet lining and red beaded attachment, an eggplant-colored sleeveless outfit featuring a lavender frill, black and white checkered stockings, and matching eggplant-colored shoes. She is generally calm and earnest. Her name, Maeve, carries the meaning "intoxicating" or "she who intoxicates" in Irish and Gaelic.