Sconosciuto famiglia is an unknown (that's also the translate of the name "Sconosciuto") family. No one knows something about them, someone already knew there was a family called like that, but the members, their headquarters and territories are unknown. Only Cristal and the Neveria seem to know about him and his family.
The only known member is Guy, the boss and old friend of Cristal, but he's always hidden behind a white mask and a long cloak, so no one knows his face.