The characters combine to create a powerful image: “to walk into the fire and enter a demonic state.” The “fire” of one's own passion or internal energy goes out of control, leading to a “demonic” or insane mindset.
The roots of `走火入魔` are deep in Chinese Wuxia (武侠) culture—the genre of martial arts heroes and fantasy. In these stories, and in the real-world practice of Qigong (气功), it describes a practitioner's worst nightmare: their qi (气), or life-force energy, deviates from its proper channels during meditation or training. This “qigong deviation” is believed to cause severe physical and psychological damage, from psychosis to paralysis. While the Western concept of “going off the deep end” or “being obsessed” is similar, `走火入魔` carries a unique cultural weight. The Western phrases often imply a simple loss of control or an intense interest. `走火入魔`, however, suggests a corruption from within, a process where a positive pursuit (like self-improvement or dedication) becomes a self-destructive force. It reflects the Taoist and Buddhist emphasis on balance (平衡) and avoiding extremes. Pushing too hard, even with good intentions, can lead you down a dark path.
In modern Mandarin, `走火入魔` has shed its literal, supernatural meaning and is used figuratively to describe an unhealthy obsession in any field. It always carries a strong negative connotation, suggesting that the person's obsession is worrying and detrimental to their well-being.