80th branch is a small island on the southern part of the West Blue. It is a branch of the Marines, only one of their many scattered across the world. This branch is said to be one of the branches used to store and develop weapons that will be supplied to other branches.

The island is not a very large one, thus there is not a part of the island that is not concrete thanks to the Marines. It's defences are solid, focusing more on attacking back then actually taking a hit. Across the bases are many cannons to support this, earning this branch the nickname "Gunpowder Branch".