Ghouls are creatures of folklore said to feast on the dead, including their own.
According to Old Nan, wildlings consort with giants and ghouls beyond the Wall.
Maesters consider Sothoryi who feast on their own dead to be ghouls.
Yeen in Sothoryos is threatened by ghouls. When Nymeria led the Rhoynar to Sothoryos, the Rhoynish colony at Yeen was attacked by brindled ghouls.
Rangers of the Night's Watch claim that the ruins of Hardhome are haunted by ghouls, demons, and bloodthirsty ghosts.