As with almost every battle of the game, there is no one "best" way to beat this boss, but for this tip I'm playing into the fact that he's blind and weak versus fire. Used body form, with a dragon long sword +5, light armor(wizard set, starting set for royalty origin), thief ring, and regenerator ring (which I didn't need since he didn't touch me.) If you walk slowly, he bumbles around and attacks random spots. When you see him start to attack, roll in, 3-hit-combo him, and roll out. Repeat until the Old Hero is dead. The fight took a couple minutes, but was easy.