From the Suikoden III manual:
"A young but skillful rider known to cross the vast prairies of Grassland by steed in the early morning. Hugo is the son of Lucia, Karaya Clan Chief, who assigns him the mission of delivering an official message to the hostile nation of Zexen. As the son of his tribe's chief, he sets off to help bring peace to a land that has known much grief."
The Tensyo Star of Suikoden III, Hugo is one of the "primary" characters in the game, and is not the same as the Hugo appearing in Suikoden I.