Nebulandia, also called, “Island of fog”, is an island situated in the New World. It is also a Marine Base. The island appeared in the One Piece TV special: Adventure of Nebulandia. It is a non-canon, and doesn’t have anything to do with the canon story of One Piece.
One Piece TV Special: Adventure of Nebulandia
After Komei imprisoned Zoro, Sanji, Porche, and Hamburg, the other Straw Hat Pirates and Foxy and Kansho proceeded to rescue them on this island. Komei came very close to killing Luffy and capturing every Straw Hat. But, the Kinoconda—whom they had befriended on Mushroom Island—and Brook, Tony Tony Chopper, and the other Foxy Pirates helped save the day.
While Luffy and Komei engaged in battle, the pirates repelled the Marines while the giant Kinoconda severely damaged the station. To weaken the Devil Fruit users during their battle, Komei damaged the caldera walls to allow seawater in, but this completely destroyed the base. However, before the Straw Hat captain used his Red Hawk to defeat Komei, Luffy and Foxy drained the seawater. After that, the pirates departed Nebulandia and went back to Mushroom Island.
The island has an enormous crater and several rocky outcrops, which the Marines used to build outposts. The caldera's basin is below sea level. A geyser in the form of a volcano surrounds the caldera's core and constantly ejects seawater.
When dusk sets, the geyser in the island's center discharges a seawater mist that collects in the Caldera's basin. All Devil Fruit properties are negated by this mist. This makes Nebulandia a dangerous region for Devil Fruit users to enter.
An aquatic plant that resembles a vine grows on the island. As a result, it has seastone-like qualities. Users of Devil Fruit activate the plant, which will try to envelop them and weaken them for unknown causes.
Not much has been revealed about the populace of the island. However, it is also a Marine Base, and as such, it has unnamed Marines stationed on its vast.
A. The One Piece TV Special Adventure of Nebulandia is a non-canon story.
A. Adventure of Nebulandia isn’t included in the canon series of One Piece. It is instead a TV Special.
A. The Straw Hat Pirates and Foxy went to Nebulandia together to rescue Zoro, Sanji, Porche, and Hamburg.