Zazie Rainyday attends Mahora Academy's Class 3-A, communicating minimally through non-verbal gestures even during phone calls. Her Latin-script name and transfer student status indicate non-Japanese origins. Physical attributes feature tanned skin, silver hair, hazel brown eyes, a teardrop mark beneath her left eye, and a vertical scar-like facial marking, occasionally complemented by claw-like fingernails. She measures 151 cm tall and weighs 67.6 kg. As a demonfolk royal family member, she is sister to crown princess Poyo Rainyday. This heritage grants immense magical power rivaling entities like Evangeline A.K. McDowell. Residing in the Demon World, she maintains ties to Mahora through academic involvement. At Mahora, she joins the Magic and Juggling Clubs, performing acrobatics in the Nightmare Circus. Skills encompass juggling, sleight of hand, rapid costume changes, and extraordinary agility. She commands shadowy masked phantoms summoned or directed telepathically and perceives ghosts like Sayo Aisaka unaided, reflecting innate supernatural senses. During the Magical World arc, Poyo impersonates Zazie, subduing Mana, Kaede, and Setsuna with the Magic Lantern Circus artifact. This traps Negi Springfield’s group in the Eternal Garden—an illusionary realm reflecting idealized realities. Observing from Mahora, Zazie guides Negi through the illusion, explains its mechanics, and questions his resolve to return. She warns of Poyo’s hostility but declares neutrality, pledging to await Negi at Mahora. Her pactio artifact, Devil Pierrot, mirrors Poyo’s illusion manipulation. She demonstrates shadow-portal teleportation, water-walking, and remote ally surveillance. Later, she aids Chisame by summoning protective classmates, assists in saving Nagi Springfield, and combats the Mage of the Beginning, eventually becoming a guardian. In UQ Holder!, her demonic heritage manifests fully: she dons a harlequin outfit with bat-like wings and conjures a giant armored demon entity for combat and transport. Collaborating with UQ Holder, she explains the Mage of the Beginning’s powers during the Mahora Festival. Her demeanor shows increased politeness and determination while retaining calm detachment. Character development includes rare verbal moments, like declaring "serious mode" while assisting classmates in Negima!'s finale and smiling to convey gratitude. In Negima!?, she engages in pun exchanges with Mana Tatsumiya. Her role concludes as a goodwill ambassador, satisfied with Negi’s achievements.