Eruption of the Underdark

Geological / environmental event

A hole ripped open on Ersia, right in the middle of Chirider. From the chasm spewed forth hundreds of thousands of denizens from the underdark - the most terrifying of which were the Fraelings.

Fraelings were expanding territory aggressively. The conflict was pushing populations in the underdark closer and closer to the surface. Eventually, an illithid cast a powerful spell that set off a chain reaction leading to a massive explosion in the surface. As the dust settled and earth caved in, both sides had access to the surface world like never before. Instead of small caves and tunnels leading to the surface, there was now a massive hole through which armies could travel.   While most people from the underdark had trouble adapting to life on the surface, fraeling did not take long. Their incredible power and access to new, abundant sources of nutrients gave them many advantages. All of this combined to make fraelings the dominant species and began a golden age, of sorts.