- Democratic Republic of Triton
- Triton (560,000 pop)
- Protean League
- Proteus (175,000 pop)
- Nereid (92,000 pop)
- Larissa (1,200 pop)
- Galatea (3,000 pop)
- Neptunian Trojan Belt (600 pop)
- Neso (350 pop)
- Psamanthe (25 pop)
- Helium-3 mining from Neptune's cloud layer
- Carbonates and Hydrocarbons are common throughout the orbit.
- Fissile Materials, Silicates and Metals are available on Triton, but quite rare in Protean League territories, resulting in a thriving industry in commerce raiding.
- Neptune is the site of a protracted conflict between the expansive and xenophobic Protean League and the Democratic Republic of Triton, one of the largest moons in the solar system. The conflict is most popularly referred to as The Long War, as it has continued now for well over fifteen years and shows no signs of going away. Repeated diplomatic attempts to resolve the issue have utterly failed.
- While the Democratic Republic of Triton is larger and more economically powerful, it is crippled with internal political gridlock rendering the polity incapable of effectively marshaling its superior resources. The Democratic Republic of Triton's navy is substantial, but suffers from low morale and rampant cynicism among its officer corp.
- The Protean League spends a vastly higher percentage of its productivity on the construction of an ever-increasing military. Where the Democratic Republic of Triton's navy favors larger battleships, the Protean League prefers to operate a numerically superior fleet of more-expendable and more nimble frigates with only a very few larger ships.
- Still, the Protean League is not powerful enough to launch an all-out attack on Triton proper, and so has - for now - confined itself to aggressive commerce raiding, capturing smaller colonies and research stations, and slowly but surely tightening an economic noose around its larger neighbor. Until recently the Democratic Republic of Triton's populace considered the Protean League's actions merely a nuisance, but with the loss of a few high-profile mining and research bases in Neptune's Trojan Belt there is an increasing fear that the Protean League may actually someday be able to force the Democratic Republic of Triton itself to its knees.
- Most of the solar system's polities are at least tacitly friendly with the Democratic Republic of Triton and hostile to the Protean League, but there are notable exceptions in both directions:
- The Oceanic League on Earth is extremely friendly with the Democratic Republic of Triton, and was in fact the main source of the Democratic Republic of Triton's initial population. The Oceanic League today remains one of the primary suppliers of military aid to Triton and has provided numerous military officer exchange programs and even several aging battleships.
- The Commonwealth of Callisto of Jupiter is similarly friendly, though both are embroiled in conflicts and as such neither is able to provide much material aid to the other.
- The Plutonian Assembly and the Sedna All-Thing are both very sympathetic to the Democratic Republic of Triton and have even been known to occasionally convince the Kuiper Compact to send direct military aid.
- Haumea is the Protean League's only true political ally in the solar system (although a number of other polities are perfectly happy to remain neutral with the autocratic and xenophobic state). By extension, Haumea has been quite active in the conduction of sabotage and assorted acts of hostility - including terrorist attacks targeting civilians - against the Democratic Republic of Triton.
- On the two most distant moons of Neptune - in fact, the most distant moons of any moons in the solar system from their own primary - the Alliance has set up a solitary, small mining operation on Neso, and a tiny research station on Psamanthe. The Alliance has been careful to not antagonize either the Democratic Republic of Triton or the Protean League, and has made no moves on either. Neither the Democratic Republic of Triton nor the Protean League trusts the Alliance's intentions, however, and both keep a close eye on Alliance operations in the area.
- Neptune is, along with Uranus, Saturn, and Jupiter, one of the solar system's gas giants. It is slightly larger than Uranus, but considerably smaller than both Jupiter and Saturn.
- Unlike Jupiter and Saturn, Neptune - as well as Uranus - have a higher proportion of water, ammonia, and methane ices. These volatiles serve as a major target for mining operations in the orbit, along with Helium-3, a fuel that is becoming increasingly important in the solar system's economy.
- Neptune does have rings - the Adams Ring, Le Verrier Ring, the Galle Ring, the Lassell Ring, and the Arago Ring, but these are all quite faint and indistinct in comparison to Saturn's rings.
- Neptune's and Pluto's orbits are such that sometimes one, sometimes the other are farther out. This is a side effect of the fact that Neptune's gravity has a profound effect on the orbits of many of the dwarf planets of the Kuiper Belt - Triton itself is believed to have once been a dwarf planet from the Kuiper Belt.
- Unlike Uranus, Neptune's atmosphere is very dynamic and evinces aggressive and dynamic storm systems. Most winds on Neptune move in a direction opposite the planet's own rotation.
- Although Neptune is much farther from the Sun than Uranus - Neptune receives less than half the light Uranus does - their surface temperatures are actually comparable due to Neptune's higher internal heating.
- Triton is one of the solar system's largest moons, and consists of over 99% of the mass in orbit around Neptune in a synchronous orbit that is (very) slowly decaying, and will in several billion years eventually be consumed by Neptune.