Aisa is a young Shandia girl from Skypiea, daughter of Isa. From infancy, she displayed a unique sensitivity to conflict, crying whenever fights broke out among her tribe. This stemmed from her innate Kenbunshoku Haki, known locally as Mantra, granting her a sixth sense to perceive life forces, emotions, and the moment individuals died or fell unconscious. This ability allowed her to detect Enel's lightning-fast movements. She strongly disliked death and often rushed into danger without a plan to prevent it, driven by her Mantra awareness of fading voices. Though desiring to become a strong warrior, she initially feared the Shandia warrior leader Wyper before warming to him. Her tomboyish nature showed when she reacted with disgust to Raki's suggestion she grow her hair longer for a feminine appearance. Physically small with short brown hair, Aisa typically wears a fur dress and cap. Manga depictions show a yellow dress with white lines and green cap accents; the anime shows a brown dress and yellow-white cap. She is often barefoot in the anime but wears sandals in the manga, except during a haircut. She carries a tan satchel with yellow buckles and occasionally wears a hairclip. After two years, she grows taller with slightly larger wings. She adopts a Wagomuland cap and grows her hair into pigtails, following Raki's advice. During the Skypiea conflict, Aisa frequently sneaked onto Upper Yard to collect sacred Vearth (Blue Sea soil) for sky agriculture. After sensing two deaths via Mantra, she alerted Wyper, prompting the Shandia attack on Enel's forces. When more voices disappeared, she attempted to return to Upper Yard but was stranded when her Waver broke. Sky sharks attacked her until Pagaya and Conis rescued her, bringing her to the Straw Hat Pirates' ship, the Going Merry. There, her Mantra detected continuous loss of life, causing distress. She later tried to save her friends alone, leading to misadventures: chased by Divine Soldiers with Nami, swallowed by the giant python Nola, and encountering Luffy inside the creature. After escaping Nola, she guided Luffy to Enel, witnessing his immunity to Enel's lightning. She and Pierre attempted to rescue Luffy when Enel kicked him off the Ark Maxim but were struck down by Enel's lightning. Surviving the fall, she directed Luffy toward Giant Jack to pursue Enel. In the climax, she urged Wyper not to sacrifice himself, but he used a Reject Dial to topple the beanstalk supporting Enel's ark. She tearfully witnessed Luffy's victory and the ringing of Skypiea's golden bell. After the conflict, Raki trimmed Aisa's hair, noting she no longer needed short hair or weapons due to peace. Aisa was the only local to bid farewell to the departing Straw Hats, thanking them for saving the island. She viewed Luffy as a role model, aspiring to become a warrior like him. Two years later, she worked at Wagomuland amusement park as the "Cloud Ball Girl," selling cloud balloons to children. In the non-canon "One Piece: Stampede," she attended the Pirates Festival with Conis, buying takoyaki from Hatchan. Aisa maintained a close friendship with Raki, often bringing her Vearth gifts. While their exact familial relationship is ambiguous—Raki refers to Aisa's mother as "aunt"—the term may indicate respect rather than kinship. Initially perceiving the Straw Hats as threats, she grew to admire them during the war against Enel, especially their efforts to protect Skypiea. She remained wary of Skypieans like Pagaya and Conis until their pet Su warmed up to her. She also distrusted Gan Fall, blaming him for Enel's tyranny, and threatened him with her Burn Blade—a weapon carried for self-defense but never used in combat.