If your army includes Tehenhauin, you may upgrade any units of Skink Cohorts, Skink Skirmishers, Horned One Riders, Terradon Riders or Ripperdactyl Riders in your army so that the Skinks have +1 WS, as well as Devastating Charge, Hatred (Skaven) and Immunity (Poisoned Attacks) for 2 points per model. They may not take any Sacred Spawning.