What is the theme in Manual of the Warrior of Light by Paulo Coelho?

Madness is a central theme in this story. A Warrior of the Light has to go head first into a bloody battle. To do this, he needs to have a touch of madness, which gives him the strength and detachment he needs to go into a fight. A Warrior is much like a normal person and has family and friends about whom he cares. A normal person would find it exceedingly difficult to leave behind everything that he or she knows to go and fight a battle that he or she may not benefit from directly, if at all. Regular people would not give up their comfortable lives to fight for another person's cause, and could never say goodbye to their friends, convinced that he or she may never see them again.