Walkthrough for the "Tribes of the East" expansion.

Don't return to the first ship you arrived on!
Near the green castle, build another ship (there's a shipyard below the castle; you need to go around the castle on the right and you'll see it) and sail SOUTH (there's another shipyard shown there, already on the turquoise island). Sail to it, disembark, and follow the path west. There, you will meet the turquoise hero.