Ruluka Island is an anime-only island in the Grand Line. A phenomenon, known as the Rainbow Mist, is found near it. Years ago, the city was burned down by a pirate, who became its current mayor, Wetton. He forced people to pay exorbitant taxes for nearly everything, even taxing people for eating food and drink they already paid for to satisfy both his greed and to complete the Rainbow Tower, which is meant to reach the Rainbow Mist.
However, Rapanui, as a Marine officer, arrested Wetton and ended his tyranny.