This is the forum for helping you out if you're stuck in Grimrock 2 or if you want to discuss about the mysteries of the Isle of Nex. Warning: forum contains spoilers!
Just elaborates on the story. You see, there is a reason the island is filled with monsters and traps, and whoever created it, is more interested in those who are up to the challenge than those who aren't. Also maybe hints at the games's two endings and maybe not. Don't think into it too much: it is a game about dungeon crawling and monster slaying.
I personaly thought when i read that, that it gives a hint ofr the guards of the gem which was there. So i thought that it tells me, take it and leave as fast as you can. I did that and monsters came to that place after taking the game and i could slain them from the other side...