Ammo Knights

The Ammo Knights are the royal guard protecting the Neptune Family in the Ryugu Kingdom on Fish-Man Island. They are recognizable by their spiral-shell helmets and tridents and are tasked with upholding order across the undersea realm.

Each Ammo Knight wears a large striped shell coiled like an ammonite as headgear, with matching shells serving as shoulder protection. A black covering conceals their eyes, and a single horn juts forward from the helmet like a unicorn's horn.

As the sworn protectors of the Ryugu Kingdom's royal house, the Ammo Knights are considered formidable and capable of keeping the peace throughout the kingdom. Even so, the New Fish-Man Pirates managed to overpower them, though only by relying on energy steroids, suggesting the guards rank above the average fish-man in raw strength.

No, the Ammo Knights failed to complete their orders against the Straw Hat Pirates. They were sent to round up the crew across Fish-Man Island but could not stop them, and they were later overcome at the palace and left bound alongside Neptune and his ministers.

Toward the climax of the Fish-Man Island arc, several Ammo Knights were stationed in the control room governing the island's air tank. There, they helped Luffy and the princes fire a blast of air that pushed the colossal ship Noah off its collision course with the island.