Pavwood Forest

On the western side of Agria, Pavwood forest is a normal forest in an area that is mostly hills. However, when the leader of the Dragon Initiate, Elvereth Mondathia, found a cave within the forest and began experiments, everything changed.

Using Dragon blood to try to get creatures to grow in size and power, he eventually abandoned his experiments when a tree he experimented on grew into a monstrous Treant that breathed lightning. Also, a spider he injected with blood, once abandoned, began to grow continuously within the cave until the party discovered it. The rage from the Treant began to affect the inhabitants of the forest, causing them to attack nearby settlements, specifically Hillgrove.

Eventually the party stumbled onto this and put a stop to the monstrous Treant, causing the forest to mostly go back to normal.