Kouko Shirasaki is a character within the anthology series Junji Ito Maniac: Japanese Tales of the Macabre, specifically featured in the segment known as Library Vision. She is introduced as the wife of Gorou Shirasaki, a man she came to love after being impressed by his sharp intellect and his fervent dedication to reading. That initial admiration, grounded in a shared appreciation for literature, becomes the foundation of their relationship. However, once they are married, Kouko finds herself consistently shut out from one of the most significant aspects of her husband's life. Gorou possesses a vast private library containing an immense collection of books, yet he enforces a strict rule that Kouko is never permitted to take any volume from its shelves. This prohibition leaves her feeling alienated and isolated within her own home, as she is denied access to the very passion that first drew her toward him.

Her role in the story centers on her position as a witness to her husband's psychological unraveling. When Gorou falls ill, consumed by anxiety after discovering that a small number of books appear to be missing from his collection, Kouko's worry compels her to investigate. She turns to his personal diaries, hoping to understand what is happening to him. Through these writings, she becomes a silent observer of the fixation and distress that grip him. As his condition worsens into psychosis, Kouko is depicted as essentially helpless, able only to watch as his mind deteriorates. The key relationship in her narrative is the one with Gorou, a bond that shifts from admiration to estrangement and ultimately to a powerless state of alarm. Kouko possesses no supernatural abilities or extraordinary powers; she is an ordinary person caught in a domestic horror driven by another's obsession. Her development traces a quiet arc from longing and frustration to desperate concern, but she does not achieve any clear resolution, remaining trapped in a situation that she cannot remedy. Her presence in the segment underscores the horror of emotional distance within a marriage and the dread of witnessing a loved one's gradual collapse.