This ancient runic staff came into Bloodbournes possession during their initial stay in Asdelor. A mysterious figure left it behind with instructions it be delivered to the dragon man. Upon gaining the metallic weapon Bloodbourne realized the thing was alive. Not only could it communicate with him telepathically but it was both highly intelligent and knowledgeable of current events. Whats further.. the staff was carried by his grandfather long ago in many great battles, in fact the staff has been part of his hereditary bloodline for generations. Even its alien metallic surface is scribed with the family crest.
Ever since the party explored the Great Mausaleum the Osmus has been silent.