Kōko is a character from the anime adaptation of Junji Ito's story "Library Vision," which is part of the anthology series. She is the wife of Goro, a man who becomes obsessively fixated on his vast library. Kōko's background is that of a domestic spouse living with her husband in a home filled with books. Her personality is defined by concern and anxiety as she watches Goro's library obsession escalate into a dangerous and irrational fixation. She tries to reason with him and remind him of the outside world, but her efforts are met with resistance. Her primary motivation is to protect her husband from the negative consequences of his obsession and to restore normalcy to their lives. Her role in the story is that of a witness and a voice of caution, highlighting the tragic disconnect between her perspective and Goro's delusion. Her key relationship is with Goro, which is strained by his growing mania and her inability to intervene effectively. Throughout the story, Kōko develops from a worried but largely passive figure into someone who experiences the full horror of her husband's transformation, but she does not undergo any positive change or gain new abilities. She has no supernatural powers and is an ordinary person caught in an extraordinary and disturbing situation.