Mayumi Thyme is a supporting character in the anime Shuffle! Memories. She is a second-year student at Verbena Academy and a classmate of the protagonist Rin Tsuchimi. Mayumi is of mixed heritage, being half-human and half-devil, which is the reason for her distinctive heterochromatic eyes. Despite her demon blood, she exhibits none of the common physical traits associated with devils, such as long ears or magical powers, and appears as an ordinary human girl. She is notably stylish and attractive, though she has an inferiority complex about her small bust size, which is often the subject of teasing from Rin and his friend Itsuki. Mayumi, however, takes pride in this trait, rationalizing that being below average makes her a rarity sought after by a select group of men.

Mayumi has a bubbly, hyperactive, and curious personality. She is always on the lookout for news and gossip, which drives her to carry a digital camera everywhere. This curiosity often leads her to rush into situations without thinking, making her something of a troublemaker. Her academic performance is poor, and she regularly attends supplementary classes, yet she possesses a sharp mind for trivial knowledge and is a skilled negotiator. She gets along well with her classmates, especially Kaede Fuyou, with whom she shares a close friendship. Mayumi's role in the story is primarily that of a friend and comic relief, providing levity through her energetic antics and her constant quest for information. She does not undergo significant character development over the course of Shuffle! Memories, remaining a consistent source of humor and lighthearted interaction within the group. Her notable abilities lie in her quick thinking, her knack for bargaining, and her talent for sniffing out interesting stories, though she lacks any supernatural or combat-oriented skills.