Sebio is the city located at the southern part of Dressrosa. It is where Riku Dold III attacked his own people as he was controlled by Donquixote Doflamingo.
Ten years ago, Sebio had fairly modest buildings and homes with simple architecture and was surrounded mostly by woods. Since then, they have updated to larger buildings with architecture similar to that of other Dressrosa towns like Acacia. They also have a sizable port.
Ten years prior to the current timeline, Doflamingo controlled Dressrosa's King Riku using his ability, and forced him to attack his own people.
After Sugar was knocked unconscious, all of the toys working at the port transformed into their original forms. The former toys, who were pirates, began to ravage the town.