There was a process of hero-worship, even in medieval times, of such figures as Saladin and Richard the Lionhearted who were praised not only for their military skills but, above all, for their chivalry. As they roamed the countryside, they spared no effort in pillaging towns and farms for food.
Most Crusades, however, were directed at Muslim states in the Middle East, with the first starting in and the last in The Crusades were an incredibly violent undertaking, even by medieval standards.
Some of it was also later developments of the Muslims themselves.
Local church leaders certainly didn't mind, and they encouraged locals in the veneration of these relics. I'm not sure that they got very far, although they did manage to join other armies following Emich of Leisingen who asserted that a cross miraculously appeared on his chest, certifying him for leadership.
All the spoils of war were given back to the church since it was a holy crusade.
More crusades was one consequence of the First Crusade because even though this crusade in a sense was successful, it failed in keeping peace in the holy land and the Christians failed to keep Jerusalem and their Crusader States.
The Crusades exemplify the way in which religious devotion can become a violent act in a grand, cosmic drama of good vs.