The concept of 妖怪 (yāoguài) is deeply woven into the fabric of Chinese culture, shaped largely by Taoist and Buddhist beliefs. They are not simply evil creatures to be slain; they represent a disruption of the natural order and often serve as moral foils in stories. The most famous collection of 妖怪 tales is the classic novel Journey to the West (《西游记》). On their pilgrimage, the heroes Sun Wukong, Xuanzang, and their companions encounter a vast array of 妖怪, each with a unique backstory, motivation, and weakness. These 妖怪 often want to eat the monk Xuanzang to gain immortality, testing the heroes' strength, wit, and virtue. A key cultural distinction from Western monsters is the concept of origin and transformation. A Western vampire or werewolf is often cursed or part of a specific monstrous race. In contrast, a 妖怪 becomes what it is through a long process of absorbing essence (a Taoist concept called 修炼, xiūliàn). A thousand-year-old fox can become a beautiful woman; a giant boulder can gain a spirit and the ability to speak. This means 妖怪 are not inherently evil from birth. Their morality—good, evil, or neutral—is often a result of their experiences and choices. For example, in the beloved folktale Legend of the White Snake (《白蛇传》), the main character is a benevolent snake 妖怪 who falls in love with a human.
While its roots are in folklore, 妖怪 (yāoguài) is a living term used in various modern contexts.
A common pitfall for learners is to use 妖怪 (yāoguài) as a catch-all term for any supernatural evil. It's more specific than that. The key is to distinguish it from 鬼 (guǐ) and 魔 (mó).