Nami Kojima hails from a wealthy family and grew up as a sheltered noblewoman, initially naive about the world beyond her privilege. Her worldview transforms when encountering Leina Haruka, a new classmate Nami believes embodies a prophecy from "Three Girls of Aileas"—a sword-wielding heroine destined to vanquish the darkness of Tide Tyrant. Prior to Leina’s arrival, Nami’s fixation on this prophecy isolates her from peers, straining social bonds.

Her background ties to "Alice's Adventures in Wonderland" through a broken fob watch, gifted by her mother and adorned with story motifs. This watch becomes pivotal during a confrontation, exposing Tide Tyrant’s true identity. When a classmate disappears, Nami helps sound the alarm and aids Leina in combat, revealing unexpected bravery and resourcefulness despite her sheltered past. The watch is shattered to defeat Tide Tyrant, unlocking shards of Leina’s memories.

Afterward, Nami suffers partial amnesia of the events, though her repaired watch remains a physical memento. She displays heightened contentment and a vague recollection of encountering immense strength, hinting at quiet internal growth. Evolving from a lonely, prophecy-driven student, she becomes more integrated and emotionally resilient, subtly aided by Leina’s influence.

Nami demonstrates sharp intelligence and strategic thinking, making swift decisions in danger. Assertive and confident, she voices convictions unflinchingly. As a masterful swordsman, her combat prowess ranks among her world’s finest, cementing her role as both a tactical and emotional ally.