Full Name: Tadayasu Souemon Sawaki Background: The second son of the long-established seed starter shop Sawaki Yeast. He grew up helping with the family business from a young age. He entered the Faculty of Agriculture at a certain agricultural university through a recommendation due to his grandfather's connection with Professor Itsuki. Male. Traits: Possesses the special ability to see bacteria and viruses with the naked eye, and can communicate with or capture them. Everyone knows he has this ability. When his power is active, the microbes float around him as stylized, deformed characters. His appearance is that of a perfectly ordinary first-year college student. Personality: A pacifist and passive, with a somewhat unreliable side that is easily swayed. However, he is kind and serious at heart. While he gets tossed around by the wild antics of the unique individuals surrounding him, he possesses the passion and sincerity to never abandon people or microbes in trouble.

Full Name: Kei Yuki Background: The son of the Yuki Sake Brewery. He is Sawaki's childhood friend and best friend. Troubled by the management of his family's brewery and his own future, he disappeared from campus for a time. Male. First-year university student. Traits: Appears dressed in black Gothic Lolita clothing (cross-dressing) and lives his campus life that way. He is even more beautiful than Sawaki and has extensive knowledge of sake and fermentation. Personality: Cool, rational, and highly intelligent. He has a calm perspective on his surroundings, but he harbors a very strong obsession and deep friendship (or perhaps an attachment that could be seen as more) toward Sawaki, and will take bold actions for his sake. He talks quite a bit.

Full Name: Keizo Itsuki Background: A professor at the agricultural university and the head of the Itsuki Lab. He is an old acquaintance of Sawaki's grandfather. He is a world authority on fermentation and microbiology, with powerful connections in politics, business, and academic societies both domestically and abroad. Male. Traits: An elderly professor with white hair and round glasses, exuding a suspicious atmosphere. He researches and stores fermented foods from all over the world (such as surströmming and kiviak), turning his lab into a suspicious experimental ground. His experiments are wide-ranging, mainly involving the lab members in making miso, soy sauce, and sake. He trusts Sawaki's ability but does not exploit it. Personality: A slippery character, elusive and fundamentally an eccentric. However, his enthusiasm for academia and microbes is genuine. He is a deep-hearted mentor who watches over and guides his students warmly (though sometimes bluntly).

Full Name: Haruka Hasegawa Background: A graduate student in the Itsuki Lab (1st year master's). She is the daughter of a wealthy apparel company president but has long suffered from conflict with her overbearing father and a forced political marriage. Female. Traits: Has a stunning physique and typically wears slit skirts or bondage-style outfits under her lab coat. She has an extremely high tolerance for alcohol. Personality: Haughty and sadistic, with a foul-mouthed and aggressive personality. However, she is essentially a reliable, big-sister type who looks after others, combining a delicate side with tsundere elements. Through the rescue operation involving her lab colleagues (Misato and Kawahama), she gains the strength to walk her own path.

Full Name: Kaoru Misato Background: A second-year student in the Itsuki Lab. He is constantly suffering from a lack of money. Male. Traits: A wild appearance with long hair tied back. He has an abnormally high drive for making money, such as brewing moonshine on campus or starting a craft beer business. Personality: Acts like a middle-aged man. However, he is loyal to his friends and compassionate, a man of action who pushes through the mud toward goals he has set (like brewing beer or rescuing Hasegawa). Speaks with a regional drawl (Kansai accent).

Full Name: Takuma Kawahama Background: A second-year student in the Itsuki Lab. A returnee from Mexico. He has deep knowledge of insects and the fermentation and food culture of Central and South America. Male. Misato's best friend. Traits: Short and chubby. He is always paired up with Misato, showing a perfectly synchronized partnership. Personality: Like Misato, he is greedy and opportunistic, but he is quick-witted and excels at information gathering. He possesses a unique set of values typical of a returnee and is very resourceful.

Full Name: Hazuki Oikawa Background: A first-year student in the Faculty of Agriculture and a classmate of Sawaki and Kei. Female. First-year university student. Traits: An extreme sterilization maniac who always carries disinfectant spray and a mask. She initially didn't believe Sawaki's claim that he could see microbes at all. Personality: A feisty, serious, and high-achieving type with a strong sense of justice. Due to her germaphobia, she initially repelled the sloppiness and filth of the Itsuki Lab, but through activities like beer brewing, she awakens to the depth of fermentation and becomes a regular and the straight-man of the lab.

Full Name: Aoi Mutou Background: The only seminar student in the Itsuki Lab (4th year). She has a glamorous past as a former Miss Ag-U. Female. Traits: A beautiful woman with a great figure, but she is usually crude and wears a tracksuit. She is a very bad drunk, losing her memory or getting belligerent with those around her when intoxicated. Personality: Contrary to her glamorous appearance, her personality is frank and casual. She is tough enough to fly all over Japan and the world for fieldwork and surveys on fermented foods.