Fei and Natsume forged an inseparable bond while growing up in the Tanker Orphanage, their shared hardships solidifying a deep childhood friendship. Upon leaving, Fei took on the gritty role of processing Gadoll remains as a demolition worker. Though she outwardly supported Natsume’s dream of joining the warrior elite called the Power, Fei privately welcomed her friend’s reassignment to a less perilous maintenance position, her anxiety over Natsume’s safety outweighing any idealism about combat glory.

With long brown hair meticulously braided and warm brown eyes reflecting her initially nurturing demeanor, Fei’s kindness gradually curdles into unease as Natsume trains under Kaburagi’s mentorship. While Natsume defies societal boundaries, Fei clings to the rigid stability of their world, her reluctance to question the status quo masking unspoken fears and simmering envy.

Natsume’s growing prowess with combat prosthetics and newfound confidence fractures their dynamic. When crisis demands non-combat personnel like Fei to assist in a high-stakes mission, she erupts at Natsume, condemning her ambition as reckless and self-centered. The outburst lays bare Fei’s embittered struggle to reconcile Natsume’s metamorphosis with her own stifled desires.

Their diverging paths—Fei’s defensive adherence to routine versus Natsume’s relentless drive—expose fault lines of complacency and aspiration. Fei’s orphanage upbringing and labor-intensive life shape her risk-averse pragmatism, yet her unresolved tensions with Natsume linger, untempered by personal growth or closure.