Tree Spirits are a unique creature, being neither plant nor monster; rather some blend in-between.
They occur when a burst of Kronic energy is released in a small enough form-factor that it can wholly penetrate a healthy tree.
Upon doing so, the tree comes to life, gaining a kind of sentience of its own.

Despite its sentience, it doesn't seem too interested in much besides just having a peaceful existence.
If attacked, they release pseudo-magical sprites that hunt down the attacker in an act of defence, before going back into hibernation.

Notably, they are particularly vulnerable to fire-based damage as would be expected of their heritage.