Akari Haeno is a third-year middle school student and the leader of the idol unit Tetrarkhia. She has very long orange hair, typically styled with a large braid across the top of her head and held in place by a grey plaid bow. Loose tufts frame her ears, and her bangs are centered with longer strands that flare outward near her ears. Her eyes are a rounded purple hue. For casual wear, she favors a distinctly girly and sweet aesthetic, often seen in pink and white outfits with frilly accents, skirts, and various pieces of jewelry and necklaces. Her stage costume aligns with the rest of Tetrarkhia but is set apart by the addition of black bike shorts or leggings.

Outwardly calm and gentle, Akari harbors a deeply burning passion beneath her polite and serious demeanor. She is dedicated to her ambitions as an idol and acts as the mood maker within the group, credited with uniting the unit's diverse personalities. When angered, she becomes a force no one can oppose. Her personal interests include shopping and collecting ribbons, and she dislikes bugs.

A humorous trait shared among the Tetrarkhia members is that each one, including Akari, believes herself to be the true leader of the unit. Her given name, Akari, combines the characters for "vermilion red" and "white jasmine," with the vermilion character also referencing the Vermilion Bird, a symbol of the south. Her surname, Haeno, incorporates the meanings "south," "wind," and "field," fitting a pattern in which every Tetrarkhia member's surname contains a cardinal direction—south being hers.

She was born on October 12, under the zodiac sign Libra, and has blood type A.