In Heretic Kingdoms 1: the Inquisition, while in Dreamworld, I can see here and there some glowing pentagrams on the ground, called Hex Marks. I can interact with them, but they just disappear after it, and it seems nothing more happens.

What are they for?

Just in case somebody is looking for answer to same question: those provide extra points to improve your melee / ranged / speed etc. attributes.
Collect enough (I think, it was 100) and you can increase your stats in Character menu (precc "C" to open it)