Ruluka Island is the island that was shown in the Rainbow Mist Arc. This island is seen during the filler arc from episodes 139-143 in One Piece.
The Ruluka Island Arc starts with the Going Merry being chased by Marines led by Major Rapanui Pasqua and Isoka. Luffy and his crew could barely escape when the Marine Major’s ship shot at them and they accidentally hit their other Marine ship and sank it.
The Straw Hats then made their way to Ruluka Island and got to know that the person who dictated them is an old pirate. This person is overcharging the taxes so that he can get the Rainbow Tower built, as a scientist had discovered something known as ‘Rainbow Mist’.
The scientist was sponsored by the mayor of Ruluka Island. The Going Merry got caught up in the Rainbow Mist. When they were lost in the mist, the crew discovered a group of children who had been trapped in it for years.
When the Straw Hats find their way out from the mist, they are not able to locate the children. The Marines had arrived again to apparently arrest them but they turn out to be the kids that they had seen. The kids say that there is no more place on the ship as the Mayor and his wicked gang have been tied and locked up there. The Straw Hats leave Ruluka Island.
Wetton is the main antagonist of Ruluka Island. He was the captain of Wetton Pirates before he became the Mayor of Ruluka Island.
Henzo is a scientist known for his research on Rainbow Mist. He is known to be careless and rude among strangers.
Unlike in the manga, where the Going Merry was heavily damaged at the end of the Arabasta Arc by Hina's attack, in the anime, this arc depicts how the Going Merry began to severely fall apart, seeing it get blasted out of Ape's Concert with too much force for the ship to handle, causing the figurehead to break off, and have one of the masts snap in two and collapse on a railing, tearing it apart as well. Then, the ship is patched up in Ruluka just before heading out.
A. Henzo was a scientist who was researching the ‘Rainbow Mist’.
A. Wetton is the mayor of Ruluka Island.
A. Ruluka Island is located in Paradise.