Although Shadow Lords cannot begin with the Ally background, cultists can depend on their associates to ally with them. The drawback is that you must keep this alliance a secret. Belonging to a Shadow Lord cult is a disgrace that even fellow Shadow Lords will not tolerate. A cult will still be devoted to a cultist without this background, but a Lord with Cultist Allies will find them to be even more useful than normal. This is in most respects identical to the Allies Background. The only notable difference is the cult's fanaticism.