The Wraith were a race of information seekers, that had information on law breakers in the universe. The Seventh Doctor wanted some information from them about Kurt Schalk and where the Daleks had taken them. They accepted bones as a form of payment. They lived on Lamuria. They wanted to punish the descendants of the criminals in their database. When the Doctor sent Davros to them, they haunted him as payment for the debt that the Doctor owed him. (AUDIO: Daleks Among Us)