Atoll is a water fortress that is located in Paradise and it taken by force by Deacon. It is made up of metal features like balconies with a large tower above the narrow dock that is at sea level.
One Piece Premier Show 2007
The only thing that is known about Atoll’s location is that it is located in Paradise.
Deacon was born and raised on the island that sunk down beneath Atoll. The water fortress was built on top of the sunken island. Later on, Deacon and his subordinates came to the fortress and took it by force, he was searching for his mother’s necklace that was lost on the seafloor below.
While Deacon was searching for it, he came across Buggy who also wanted information about the treasure. On the other end of the Atoll, the Straw Hats crew had docked after finding a necklace.
Deacon and Buggy came to a conclusion and agreed to form an alliance to work together to retrieve the treasure from the crew but then Deacon and Buggy got into an argument because Deacon stopped Buggy from firing the Buggy Balls. Buggy was defeated and he was sent flying away. Deacon saw his mother’s necklace in Nami’s hand and was happy to be reunited.
The only person who lives on Atoll is;
Deacon is a resident of Atoll. He is known to be a rough man who was hardened by sea. He can be greedy and forceful too. He really cares about Atoll a lot and the people who relate to it.
The only known wildlife on Atoll are just birds.
When Buggy left his Buggy Balls behind, they exploded and destroyed Atoll.
Atoll is a non-canon island and doesn't appear in any episode/chapter.
It is said that Atoll looks like the WaterWorld Theatre at Universal Japan.