Poison is the most terrifying thing in the world, bar none. And what kind of poison is the most terrifying? It's not the cyanide or radiation that ordinary people might think of, for the deadliest toxins, once known, can no longer cause widespread harm. Instead, it's the unknown poisons, those without names that even the afflicted do not realize have entered their systems.
At present, Master Xuanyin found himself in this very predicament. His health had been deteriorating over time, plagued by various complications, yet no cause could determine. Consequently, he attributed his deteriorating condition to the approach of his end. In reality, he was poisoned.
As for the poison in question, Gu Tao did not know.
