Twig Blights are treelike creatures standing roughly 3 ½ feet tall. Their leafless branches interlock to create a sinister humanoid shape with gnarled appendages ending in sharp, needle-like claws, which ooze a poisonous sap.
The adventurers currently do not know what these creatures are called, nor what their origins are at this point in the campaign.
Oghren Rustbeard was able to tell the heroes that the Twig Blights are the spawn of some ancient tree that he thinks is called the Tree of Garalak, or something similar. The "Tree-Man" who commands the army of the creatures is also the druid named Bedros.