Complex sentence: Colley was plagued by defeat throughout the war, and although he would receive his reinforcements, his men were so demoralized by the string of defeats and he would be killed in action at the Battle of Majuba Hill.
Split into simpler sentences: Colley was plagued by defeat throughout the war, and although he would receive his reinforcements, his men were seriously demoralized by the string of defeats. Eventully would be killed in action at the Battle of Majuba Hill.