Emi Kojima arrives as a transfer student at the protagonist’s school, masquerading under a human alias while concealing her true identity as Septem, an emissary from Evergreen—a parallel realm of magic. She forms an uneasy alliance with Bergamot, Chihaya’s father, to shield Chihaya from the antagonists Fennel and Calendula, who pursue enchanted seeds with the power to corrupt humanity.

Septem harbors unrequited romantic feelings for Bergamot, who reciprocates only through a nostalgic fixation on her haunting resemblance to his late wife, Emi Hiiragi, Chihaya’s mother. This one-sided affection fuels a fraught dynamic, as his attachment remains anchored in memory rather than genuine mutual connection.

Within the anime series, Septem spearheads efforts to reclaim stolen seeds and thwart interdimensional threats, solidifying her role as a key ally. The original OVA adaptation starkly diverges, casting her as a cunning adversary opposing the protagonists—a duality reflecting dueling narrative interpretations of her loyalties.

Her relationship with Chihaya thaws from guarded distance to fragile camaraderie after the latter rescues her from a seed-possessed creature. Septem’s reserved demeanor gradually softens; she voices gratitude and joins human gatherings, including a mansion sleepover, marking her tentative steps into human social bonds.

Her past intertwines with Evergreen’s political strife, including complicity in the seed theft and unwavering fealty to Queen Tsuyuha. These shadows of intrigue cement her dual role as both guardian of Chihaya and pawn in cross-dimensional machinations, balancing protection against the pull of hidden power struggles.