Nagisa Saito works part-time at Lemon Beach House, balancing her duties with surfing and high school life. Her indigo hair, gray eyes, and tan skin stand out against the beachside backdrop, often clad in the establishment’s uniform or a sleek black bodysuit during waves. The job fuels her passion for surfing while connecting her to an older sister, Aiko Saito, who emerges later in the anime after preceding Nagisa’s manga introduction.

Nagisa’s defining struggle is her visceral fear of Ika Musume, whom she deems a genuine menace—a stark contrast to others’ nonchalance. This tension invites relentless teasing from Ika, spurring Nagisa to briefly adopt a male persona to attract customers and evade confrontation. Though she discards the disguise, acknowledging the need to face Ika as an invader, her attempts at feigned indifference crumble when a handshake offer sends her fleeing.

Her interactions at Lemon Beach House reveal skepticism toward Eiko and Chizuru Aizawa, whose casual rapport with Ika baffles her. Nagisa’s wariness peaks when she retaliates against Ika’s sudden hugs, yet she remains a diligent employee, juggling work with surfing and fandom for magical girl and tokusatsu series.

Later manga chapters introduce friends Koike and Yamada, who visit the beach house, broadening her social ties. A temporary boyish disguise—crafted by restyling her hair—earns Ika’s “angelic” praise and customer admiration, showcasing Nagisa’s tactical adaptability despite the ruse’s brevity.

Across adaptations, Nagisa gradually settles into her role at Lemon Beach House, her fear of Ika lingering but no longer isolating her. While spin-offs and OVAs uphold her core traits, her persistent presence hints at a grudging acceptance of the unconventional community, even as she keeps one eye trained on the tentacled “invader” in her midst.