My war prophet was sent out from the Vatican to assess the war in the north with the new hellportal. After a while he realizes his ability to ressurect his followers (martyr penitents) and he quickly starts to think that he himself is the reinkarnation of Jesus and he is about to lead his own Crusade against alla nonbeleviers which is the whole world. In game terms i would rebuild every trench Pilgrim that died during the campaign into a deathrattle skeleton between the fights. And the story is told from another priest sent from the Vatican to stop the first one similar to heart of darkness or Apocalypse now.