A Hammerer’s duty is a sacred thing and, bound by oath, they will fight to the death to protect the royal blood. For the leader of the throng, a Hammerer will gladly give their life rather than face the dishonour of failure.
Your army may include one unit of Hammerers for every King or Thane it includes. Any model in a unit of Hammerers that has been joined by a King or Thane can issue and accept challenges in the same manner as a character. Should the King or Thane leave the unit for any reason, the unit loses this ability.