A young witch named Cuff first appears transformed into a bat during a snowstorm, collapsing from the cold before receiving aid from the main characters. Witch hunters murdered her parents, fostering a deep distrust of humans and leading to isolation from other witches who shunned her half-human heritage; this ostracization hindered her magical education, initially preventing her from offering insights into curses like the Duke's. Cuff works at Circus Gemini alongside Zain, a wizard bearing avian traits, performing as part of their act.

Cuff specializes in fire magic, demonstrating clear proficiency with flame-based spells. Her personality blends a playful, mischievous demeanor with moments of immaturity, including a childlike belief in figures such as Santa Claus and a tendency towards impulsive reactions—like fleeing out a window when teased about her feelings. Despite her initial reluctance to trust humans, she gradually forms a close bond with the Duke and Alice. This growing trust leads her to assist their quest to break the curse, guiding them to witchcraft gatherings like the Witches' Sabbath.

Her relationship with Zain evolves significantly; she initially rebuffs his flirtatious advances but gradually develops genuine affection for him, forming one of the series' key romantic subplots. Cuff actively participates in critical events, using her magic to locate a lost heirloom for Alice and later helping the Duke pursue Alice when she attempts to leave, showcasing her loyalty and deepening emotional investment in their fates. Her character arc emphasizes overcoming prejudice and finding belonging through genuine connections.