He was a very useful character in the beginning of the game, when you first acquire him. He continues to be of use until after the fight of Cagnazzo, since with Cagnazzo you use your 2 black mages to cast higher-level Thunder spells on him to beat him quickly. His stat growth was horrible however. In the fight before Cagnazzo, you have to be on the tip of your feet. One wrong move and he's dead, due to low HP and bad defense.