Mushi represent the most fundamental forms of life in the world. They exist without any goals or purposes other than simply "being." They stand beyond the constraints of the concepts of good and evil. Mushi can take on countless forms and are capable of mimicking elements of the natural world, such as plants, diseases, and even phenomena like rainbows. This is, however, merely a vague definition of these entities that inhabit the vibrant world, as even classifying them as a form of life would be an oversimplification. Detailed information on mushi is scarce because the majority of humans are unaware of their existence. So what are mushi and why do they exist? This is the question that a Mushishi, Ginko, constantly ponders. Mushishi are those who research mushi in hopes of understanding their place in the world's hierarchy of life. Ginko relentlessly pursues rumors of occurrences that could be tied to mushi, all for the sake of finding an answer. It could, after all, lead to the meaning of life itself.