Question

Who is or was Crunor?

We have couple items with his name like:

Crunor idol

Crunor's Heart

Does Tibia have npc which talk about that person or maybe there are books about this being?

Answer 1

Uman united himself with the earth, which we know as Tibia. And the earth bore him Crunor, the first tree. Crunor was full of charm and vitality. Also he loved his own shape, but he was wiser than Fafnar and possessed the gift of modesty. Inspired by the creation he bore from itself all the plants, small and large. And they spread out on the body of mother Tibia, like a dress - it was a delight to see. 

CRUNOR ROLE IN TIBIA

Crunor created the wolves in order to protect his forests against the orcs, but these were too numerous. Only in the deepest forests and in wild herds the wolves learned to defeat their bipedal opponents.

When the age of the wars of the unliving began, the battles were furious and bloody, and for a long time no side was apparently winning. Some humans then turned to Crunor, in order to serve from then on as druids. It is said that together with the Godly World Tree Crunor, they created many of the creatures that populate the wilderness today. However, a variety of these creatures were extinguished in the wars of that time.

NOTES Some elves worship Crunor, but they call him the Treefather. In the Kuridai caste the earth cult is more prominent than Crunor, and it is said that their complicated 'prayers' are more like summonings or invocations.

source: https://tibia.fandom.com/wiki/Crunor