Hajime Yagi, a classmate of Kazuto Iizuka, is a devoted science fiction enthusiast with a fervent interest in aliens and UFOs. Initially hostile toward Narue Nanase, she challenges Narue’s claims of extraterrestrial heritage, deploying tactics like a “basketball to the face” test and covertly trailing her on dates to collect proof. Her skepticism arises from a determination to protect the integrity of “authentic” alien portrayals in fiction, making her both a believer in cosmic possibilities and a critic of Narue’s specific assertions.

Yagi’s dynamic with Kanaka Nanase, Narue’s sister, unveils her softer edge. When Kanaka faces social difficulties, Yagi steps in as a supportive friend, bridging her own reclusive tendencies with unexpected warmth. This bond, coupled with observing Narue’s inexplicable quirks, slowly erodes Yagi’s resolve. She ceases her investigations, embracing the surreal normalcy around her and forging a heartfelt truce with Narue.

A childhood companion and neighbor of Maruo Masaki, Yagi shares a rapport tinged with playful romantic tension, exemplified when they temporarily pose as a couple to reflect the main duo’s relationship quirks. Central to her identity is her ambition to become a science fiction author. Her stories unintentionally echo real galactic histories and prophecies, leading some to mistake her fiction for clairvoyance. This thread peaks when her novel subtly foreshadows the “Serpents,” interdimensional beings pivotal to the cosmos’s unfolding drama.

Yagi’s arc—from combative doubter to steadfast confidante—showcases her resilience and maturation. Her story weaves acceptance of the inexplicable into everyday life, grounded by evolving friendships and the transformative power of imagination.