Fuuta de la Stella, a young boy with the extraordinary capacity to generate precise rankings of people, objects, or concepts based on defined criteria, wields an ability coveted by the Mafia for its unparalleled accuracy. Activating his power triggers celestial visuals—stars and galaxies swirling in his eyes—accompanied by gravitational distortions that levitate nearby objects. This skill demands direct visual contact with subjects, though its reliability wanes in rainy weather.

Initially a peripheral figure, Fuuta bonds with Tsunayoshi Sawada, whom he affectionately dubs "big brother," leading to his integration into Tsuna’s family and daily life. During a school trip orchestrated by Reborn, his rankings controversially elevate Vongola Castle above Nagoya’s famed fried shrimp, showcasing his non-combat utility. He relies on Giannini’s helicopter invention to bypass physical challenges, emphasizing his strategic approach over brute strength.

In future timelines, Fuuta evolves into a tactical asset, partnering with Bianchi to infiltrate the Millefiore Family and secure vital intelligence. Tasked with safeguarding Lambo, he balances guardianship with burgeoning responsibility, symbolized by replacing his iconic ranking book with a utilitarian suitcase.

Timid yet fiercely loyal, Fuuta avoids direct clashes—evading the Varia’s bathhouse skirmish—but displays protective diligence toward younger allies like Lambo, tempered by occasional exasperation. His reserved demeanor belies a sharp situational awareness, offering strategic insights that cement his role within the group.

Across his journey, Fuuta transitions from a solitary informant to a trusted Vongola confidant, harmonizing his analytical gifts with deepening familial bonds.