Neptune Army

Royal guards across the world are warriors sworn to the personal service of a ruling family, and almost every nation maintains its own version, often overlapping with the national military. The Ryugu Kingdom's incarnation is the Neptune Army, manned by fish-men and merfolk. King Neptune commanded it himself during Roger's era, and in the present its leadership passed to the Neptune Brothers, his sons Fukaboshi, Ryuboshi, and Manboshi. The guardsmen go into battle clad in hardened shells and armed with tridents.

The army's central duty is defending Ryugu Palace and the royal household. When Princess Shirahoshi lived under protective confinement, soldiers of the force brought her meals and stood watch over her tower in addition to their ordinary palace duties. During the Straw Hats' visit, members of the army attempted to hold the palace against the intruders. A separate, more offensive branch known as the Ammo Knights complements the comparatively defensive Neptune Army, accompanying the princes on official outings. The guard proved badly outmatched, however, when the New Fish-Man Pirates' steroid-boosted sea beasts swept it aside with ease during the uprising on Fish-Man Island.

The Neptune Brothers, Fukaboshi, Ryuboshi, and Manboshi, lead the force in the present day. Several notable figures once served in its ranks before moving on, including Jinbe, who resigned from it, and Aladine. More darkly, Hody Jones was a member during the period in which he assassinated Queen Otohime, exploiting his position before founding his own crew.