Mushishi

Some live in the deep darkness behind your eyelids. Some eat silence. Some thoughtlessly kill. Some simply drive men mad. They are known as mushi—creatures that came into being shortly after life emerged from the primordial ooze. They still exist parallel to our own lives and can only be seen by a select few. As a mushishi, Ginko is one of the few who are aware of their existense, and this young man with a sardonic smile roams from place to place with the knowledge and skill to aid those unwittingly affected by mushi.

Source: Kodansha Manga, Vol. 1

Though invisible to most, tiny creatures known as mushi lurk beneath the surface of everyday reality. They exert a strange and occasionally terrifying influence on people’s lives, and only experts known as mushishi carry the knowledge of how to deal with them. A mushishi named Ginko wanders the Japanese countryside, following rumors of various unusual occurences: a young man who dreams the future; a child with horns growing from his forehead; a boy with the power to write creatures into being; and more…

Source: Kodansha Manga, Collector's Edition Vol. 1