In 2147 AD, a "bloody aurora" suddenly appeared around the world that lasted for seven days. Unknown particles contained in the aurora (later called "light particles") penetrated the atmosphere, and those who came into contact with it would undergo "photolysis" within a few hours - the body gradually became transparent, decomposed into fine light particles, and finally dissipated. Creatures that were not in direct contact were also affected by the particles. Plants grew wildly but were toxic, and animals mutated into "photo-eclipse beasts" (their bodies were covered with fluorescent lines and were extremely aggressive).
Seven days later, the aurora disappeared, the global population dropped by 90%, and human civilization collapsed. The only remaining survivors called this disaster the "Aurora Catastrophe."
