A Stab in the Back - If you wish to take on a Warchief during a Fortress Siege, you can make things easier by dominating one or all of his Bodyguards.However, if you have dominated all of his bodyguards, you can change the parameters of the Nemesis Mission to lure the Warchief outside the borders of the fort and take him out without reinforcements. Most times, this will require infiltrating the Fortress and accomplishing a task to lure the Warchief and his bodyguards out of hiding. Challenge Headon, or Lure Your Target - Outside of a Fortress Siege, Warchiefs can still be encountered through a specific Nemesis Mission located outside the main Fortress.However, there are some key tips to keep in mind when facing a Warchief on the battlefield. The exact parameters for taking out an Overlord can vary from person to person, due to the randomized nature of the Nemesis System.
