Mnemosyne appears in the story as the mother of the mysterious woman Barbara. Her name is directly drawn from Greek mythology, where Mnemosyne is the Titaness of memory and the mother of the nine Muses. This mythological connection is central to her character, as she represents the same archetype of a primordial muse or source of artistic inspiration within the narrative. Mnemosyne is depicted as an enigmatic and ancient figure, one who seems to exist outside the normal flow of time. Her personality is marked by a knowing, almost detached wisdom, and she speaks with an air of authority about the nature of art, memory, and the fate of those who become entangled with Barbara. Her motivations appear to be tied to the preservation of a cycle involving artists and their muses, observing and occasionally intervening in the lives of those like the protagonist Yosuke Mikura. In the story, her role is that of a revelatory figure who provides crucial context about Barbara's true nature. She is the one who makes clear to Mikura that Barbara is not an ordinary woman but a muse of the arts who has resided with and inspired artists across the centuries, often leading them to both great success and eventual ruin. Mnemosyne's key relationship is with her daughter Barbara, whom she seems to understand completely, including her fickle, unpredictable, and ultimately destructive effect on human creators. She also interacts directly with Mikura, serving as a source of truth that confirms his suspicions about Barbara's supernatural origins. Through these interactions, Mnemosyne hints at a larger, recurring pattern of artists being drawn to and destroyed by their creative obsessions. Her notable ability is her deep knowledge of this cycle and her capacity to reveal hidden truths about the past, functioning almost as a living archive of the muses' influence throughout history. She does not drive the plot through action but rather through revelation, offering a perspective that transcends the immediate drama and places it within a much older, mythic framework.