maybe it's some kind of relic (The Witcher 3: Wild Hunt)

In the quest about the search for the manticore set (5th item) in the cave of the swan where you go through various tests, glitches, at the end next to the prophet you find a drawing and a skull lies on a stone, when pressed, Geralt gives out: "maybe this is some kind of relic" - what is it , is this from some quest?
And by the way, is there any sense in these tests ?, I first approached the girl and killed the brooks, helped the beggars, saved the man from the kikimor. What will happen if you don't help the poor and don't save the man, but choose a sword sticking out of a heap of gold, maybe someone tried it?