Why are the Carnisylvan creatures placed in the Human bestiary class?

Question

Why are the Hulking Carnisylvan, Dark Carnisylvan and Poisonous Carnisylvan placed in the Human bestiary class?

Seems weird because they sure look like they would fit in better in another cathegory.

Answer 1

The reason behind it is very simple... because they are in fact humans (actually women) which are metamorphosis due to curse. It is in their description 

"Carnisylvans were once humans, exposed to a dark ritual at birth they unwillingly abandoned their former lives to morph into tree-like shadow beings. Some time after coming of age they wander away to fall into a neverending slumber deep underground. Standing in pitch-black darkness, sleeping still, dreaming quaint dreams of death they await the time of joint uprising. Some are born to be chosen custodians of their siblings, awake and sentient. Dark carnisylvans are tainted by corrupted magic and try to enchant their victims with bizarre spells. It is not easy to escape the clutches of a dark carnisylvan as most of its spells are also instantly affecting the mind." ¹

It is also said by Galthen in his book Carnisylvans, Classification and Treatise²

It is described by few NPC's:

Spectulus: ...remarkably memorable. A great curse seems to transform people into a form of... wooden facsimile of a human being. ...
Spectulus: Look, I know this sounds strange but a lot of the crude conclusions from the older mages rang true. ...
Spectulus: A form of biological curse forced females to tranform after giving birth, conduct a strange ritual on their children and... ...
Spectulus: Wander out into the dark, leaving everything behind. Never to return and ultimately to carry out a complete metamorphosis. 

Innkeeper Alphonse: After a long and delightful evening in the inn, the old knight loosened up a bit. He told my old man that he was on an investigation of a strange cult. ...
Innkeeper Alphonse: I do not know if all this is related to a cult that actually existed or if it was a cult at all, I'm only telling you what I was told. ...
Innkeeper Alphonse: He told my father of strange occult rituals and that noblewoman, princesses were disappearing to follow an unknown path, never to be seen again. ³

1. https://tibia.fandom.com/wiki/Dark_Carnisylvan

2. https://tibia.fandom.com/wiki/Carnisylvans,_Classification_and_Treatise_(Book)

3. https://tibia.fandom.com/wiki/Adventures_of_Galthen_Quest