The Assassins are the followers of Lunord. The Rogues are able to become Assassins. The assassins claim that it was Lunord, not Helia, who was betrayed. You as king have reinstated Lunord to his rightful place for his assistance against the werewolf mage after his attempt to become a god. The assassins are a more powerful rogue, strong heroes who love money. In the Majesty 2 program files they are listed as "Death Knights". They are available to download for 2$.