Blight Entities
Those who are or have been affected by Blight

Blight Elementals
Creatures that spawn from Blight Nodes. 

Blight Nodes
Any structure or terrain feature in a Blight can be particularly Blighted. If so, this can open gateways from the current world into a deeper layer of the Blight. 

Accursed One
Birbs that have been directly touched by the Blight. Examples:    the Beaked Fly    the Winged Worm