Anri Hiiragi is a high school student and a central figure in the magical community of her academy, where she is known as a fellow mage in training. She shares a deep and long-standing friendship with Haruhi Kamisaka, another talented magic user, and the two are often seen navigating the challenges of their academic and magical lives together. Anri stands out with her distinctive appearance, characterized by long blonde hair that reaches her waist, which she typically styles into pigtails secured with purple ribbons. She has notable white chest-length strands of hair framing her face, complemented by her green eyes. Standing at 156 centimeters tall, she is also left-handed, a small but specific detail about her character.

Personality is where Anri truly distinguishes herself. She possesses a very strong-willed and confident nature, often coming across as competitive and stubborn in her pursuits. This self-assuredness is a double-edged sword; it fuels her determination to succeed and get what she wants, but it also leads her into trouble, particularly with her magic. She tends to be overconfident in her abilities, which can make her reckless, especially when compared to the more controlled and naturally skilled Haruhi. Despite this competitive streak, she is not defined by negativity. Her confidence is balanced by an underlying dedication to her goals and a capacity for kindness, as she is always looking for ways to help others and make people happy. While she projects an image of perfection with excellent grades in magic and good looks, she is prone to causing unintended disasters, leading to rumors that she was responsible for an explosion at the magic school building. Beneath her tough exterior, she is surprisingly quite tearful.

Anri's primary motivation is her ambition to grow as a mage. She dreams of going abroad to study at a prestigious magic institution to further her skills. To save money for this goal, she applies for a part-time job as a waitress at the Oasis cafeteria, eventually beginning to work under Otoha Kohinata. Her role in the story is largely defined by her relationship with Haruhi. She views Haruhi as a one-sided rival, constantly striving to prove herself and overcome the gap in their skills. However, Haruhi does not reciprocate this rivalry in a hostile way and instead treats Anri sweetly, which often leaves Anri flustered. This dynamic is central to her development, as she learns and grows alongside her friend, her reckless tendencies often leading to comedic or heartfelt situations that push her to improve. Her development involves gradually learning to temper her overconfidence with the wisdom that comes from experience and her friendships.

A notable ability of Anri is her proficiency in magic, even if it is prone to backfiring. She wields a unique magic wand named Paella, which was formed from her favorite feathered pen, showcasing a personal connection to her magical tools. While her academic knowledge of magic is excellent and her athleticism is high, her practical application often results in fireworks or small disasters, a trait that has become something of a legend around the school.