Björn has a deal with Magister Igsa, for every dead body that ends up in his tavern (which is more frequent than you would expect), he receives three fiery red rubies. They are cursed to be able to detect dead bodies nearby, as well as a way to be able to know the general location of the people who holds it.
Björn is the owner of the Greyberry Inn, he's a kind dwarven man with a thick bushy beard and a bald head. He wears very basic clothing and his skin is decorated in dwarvish runes tattooed on his arms and the top of his head. He not only works as the owner but also as a barkeep as well, and he knows his regular clients very well.