Marth was one King Dedede's expert knights usually tasked with manning the gates and being Hyrule's first line of defence he was respected and for good reason as he was a natural born leader. However, faced with inbeatable odds even the stongest of men fall to the darkness after getting defeated by Ganon he pledged his allegiance and worked under Ganon as his head Knight. His voice should be confident and around the mid 20's tone