Rennac, the Rich "Merchant" of Carcino, accompanied Rausten's princess L'Arachel on her travels as her seemingly unwilling bodyguard (No one knows why he became one in the first place. You probably don't want to ask.), and eventually got recruited by Ephraim's army into the war against Grado and the Demon King, where his skillls on the battlefield proved invaluable. After the war, he was summoned back to Rausten by Queen L'Arachel. He was never able to escape from his service to the self-centered new queen...he didn't try very hard, though.
Rennac entered the duelling league after Season 21, and was dragged into the arena in season 23, putting up a good fight against the infamous Angel of Death, Jaffar. Though his more, ah...sneaky abilities are of little use in a duel, Rennac's swift blade, nimble feet, and an unusually high resistance to magic for a physical fighter will certainly serve him well in future matches.