The Hero Yoshihiko and the Demon King's Castle

Yuusha Yoshihiko is a young, adventurous child who inevitably becomes The Hero Yoshihiko after the Hero Teruhiko, who went searching for a miracle herb to cure a plague which struck the village, never returned. He pulls a sacred sword from a stone within his village, which determines him as the next Hero.
Due to these events, Yoshihiko must embark on a journey to the Evil King's castle to find a cure for the plague that has stricken his village. Along the way, he finds many new companions and allies, who help Yoshihiko reach his ultimate goal.