In their original forms, the taintspawn are monstrosities and oozes; but in Monvesia, they are physical manifestations of of thought and will that have been channeled though the taint itself. Not all of these creatures are necessarily evil, however.
For complete statistics of these creatures, check out Mordenkainen's Tome of Foes.
Tainted TerritoriesThe largest tainted region of the Mortal Realm is the nation of Desolation in Raviq. The human exodus left large swaths of tainted land in both the Forest of Vines and the Sea of Sand, as well--each nearly as large as a geopolitical region of Monvesia. In Monvesia itself, tainted territories are smaller, rarely larger than can be passed through in a single hour (a league). These areas commonly mark the oldest goblinoid communities.
Edited September 13, 2018.