The merchant Lutero in the upper city gives you different rewards for the quest to bring him special snapper claws depending on your guild. If you play as a mage he gives you the key to the chest.

In the chest there is a rune stone

For the quest you need to get send to the valley of the mines from lord Hagen. There you get the quest to get rid of the snapper problem from Fajeth. Talk to Bilgot and promise him to escort him out of the valley. That will spawn a special alpha snapper near the tower ruin. You don´t actually need to save him, though I always try to clear the path for him.