TV-Series
Description
Aspergillus oryzae in Moyashimon Returns is a type of koji mold that acts as a constant companion to the protagonist, Sawaki Tadayasu, and serves as a recurring presence throughout the series. Often considered the mascot of the franchise, this specific microbe is one of several from its species that follows Sawaki, having originally come from a care package sent by his grandfather who runs a yeast and miso supply shop. This particular A. oryzae is frequently seen perched on Sawaki's shoulder, indicating a long-standing familiarity and a bond that predates the events of the story.

The personality of A. oryzae is notably abrasive and impudent, especially in its interactions with Sawaki. Unlike the more docile and sentimental experimental yeasts under the care of researcher Hasegawa Haruka, the Aspergillus molds that surround Sawaki are often rude, disparaging, and prone to making jokes at his expense. Their behavior is characterized by a consistent pattern of belittling him and applying pressure in social situations, such as when they urged him to disclose his secret ability to a classmate. This relationship is not one of passive obedience but of active, if underhanded, mentorship. Their motivations appear to align with Sawaki's best interests, but they employ a strategy of tough love, expecting him to act on his own merits while offering criticism and mockery as their primary form of engagement. When Sawaki considered traveling without traditional Japanese fermented goods like miso, for instance, the microbes aggressively pestered him, demonstrating their stake in his lifestyle and choices.

In the narrative of Moyashimon Returns, A. oryzae and its fellow Aspergillus molds play a key role in highlighting the unique and often troublesome nature of Sawaki's ability to see and communicate with microbes. They are ever-present commentators on his life, and their constant, noisy chatter contributes to his feeling that his power is often more of a burden than a gift. Their actions frequently push the plot forward by forcing Sawaki into situations he would rather avoid. The stark contrast between these rude molds and the compassionate, worried yeasts in Hasegawa's laboratory serves to illustrate the wide diversity of personalities and relationships that exist between humans and microbes within the world of the story.

The primary relationship for A. oryzae is undoubtedly with Sawaki. It is a durable but fraught friendship built on years of proximity. While the microbe is loyal and concerned with Sawaki's well-being, its method of expressing that concern is through ceaseless heckling and pressure, which often leaves Sawaki frustrated and angry. The character shows little development in terms of changing its personality; rather, its role is to be a static and reliable source of conflict and comedy. Its notable ability, shared by all microbes in the series, is sentient communication, which only Sawaki can perceive. Specifically, A. oryzae possesses a strong, assertive voice and the ability to organize with other molds to collectively influence Sawaki's decisions. Its familiarity with fermentation and traditional Japanese food production also gives it an authoritative, if rudely delivered, voice on matters relating to Sawaki's family trade and studies.