If you beat the game once and collect thirty talismans, Hotsuma's brother Moritsune becomes available. Moritsune is stronger faster, and less hearty than Hotsuma. Akujiki feeds off him more quickly. If you beat hard mode with forty talismans collected, you will unlock the OG - Joe Musashi himself. While he isn't as strong in sword play as the brothers, he can throw shurikens like no bodys business.