The Seven Last Days - Volume IV: A Mirror Filled With Light. The Seven Last Days, #4

Across a landscape blasted by war, littered with still-crawling body parts and computer-driven fighting machines that continue to fire at random, a former soldier wanders, not really alive and not really dead, finding he has the unwanted power to heal. Accompanied by his dozen despicably loathesome disciples, companioned first by Sister Clare the young mother abbess, and then by Sappho the beautiful violet-haired poet, John Boanerges seeks his own death on a cross.
This is the fourth volume in the monumental series of seven novels, "The Seven Last Days".