Winding caverns open up to Avernus, an underground lake that even boasts drinkable water. Survivors from Nerio fled to Avernus, turning it into the world's most poorly lit refugee camp. There used to be more refugees arriving every day, but now it's slowed down to a trickle. On one hand, fewer mouths to feed is good. On the other, people have lost hope that they'll ever see their missing family and friends ever again.