The Legion of the Skull
From Solium Infernum Wiki
Description
It seems the Order is not drawn to bribery: our messenger was returned without his head and hands. What motivates them? What are their wants? We must deploy agents to seek out these things, for all my research has left us empty-handed. --A private letter from Magistrate Basil to Lord Praetor Bune upon the Infernal Order of the Skull’s unexplained origin and untimely presence in the region south of the magistrate’s land holdings