There are two known breeds of Haunted Treelings. On the one hand, there are nature spirits that seek revenge for the contamination of nature. On the other hand, you find demonic entities that want to spread havoc in the world of the living. Both forms are actually spirits that have entered dead or living trees.
Haunted treelings attack every living creature on sight, either out of spite or to seek revenge. It is likely that a man and a minotaur look alike for Haunted Treeling and that so one race has to suffer for the mistakes of the other. In rare cases it is possible to calm the nature spirits if showing respect for nature, the demonic form, however, can at best be bribed to stop attacking. Some woodland communities have developed some form of coexistence with both forms. Other villages live in fear of these malicious creatures.
Haunted Treelings can easily be mistaken for normal trees which makes it easy for them to ambush their enemies. Slaying their tree form will only result in chasing the spirit out of its wooden host, but actually does not harm it at all. They are exceptionally strong and know neither pain nor fear.