Organizations in Imperia Triplica
While the Imperia would prefer to be the only organization available, others in the empire have differing opinions. The Mariner races established their own federation not only for trade but for solidarity with other non-Imperian peoples. The Sicarii, a collection of Renanim tired of being exterminated, perform acts of resistance and terrorism against the Imperia. The different cults of Marinasta act as their own entities and on some planets possess the power of nations.

Citizens of the Imperia enjoy several official organizations made explicitly for them, and are also afforded the legal ability to claim membership into almost any non-Imperian organization they desire.
Imperian Fleet
Every person born into the Imperia is required to serve in the Imperian Fleet for at least four years in order to achieve the title of "citizen." Many Imperians serve their four-year conscription and then go back to civilian life, but more enlist voluntarily and make a career out of military service. Honorable military service is the only way for someone of the Plebeian class to ascend to Equestrian.

Imperian Senate
The Imperia is governed by a Senate comprised of twelve senators, one from each Legion, with Caesar Immortalis serving as a tie-breaker if needed. Senators are elected by citizens from each social class, and are almost always veteran officers of Legion command staff. The average citizen cannot hope to achieve senatorial status, but each senator has an enormous staff of aids who assist with their duties, and these positions are within reach for the average Imperian.

Craftsman Guilds
Imperians who separate from military service generally work aboard Legions to keep them running, but some Imperians return to the planet they consider home and operate as craftsmen of that planet's popular exports.

Legion Harpastum Leagues
For the sports-minded, municipal harpastum leagues offer the opportunity to have fun with teammates playing the Imperia's most popular sport. Talented players are often recruited for their Legion's semi-professional team, and every four years they come together to compete in the Gymnasiad, which offers fame, fortune, and bragging rights to the winners.

Mariner organizations run the gamut from pro-Imperian guilds, to violently anti-Imperian terrorism groups. Although there are federations of Mariners that are meant to engender trust and cooperation between planets and systems, many Mariners tend to be insular and cautious with other species.
Marinasta Cults
The various Saints of Marinasta all have several cults dedicated to them, and it's extremely difficult to find a Mariner who isn't part of at least one of these cults. They range from the philanthropic Raven's Guild, to the relatively pro-Imperian Cultivars, to the violent and vengeful Prophets of the Auk.

Mariner Federation
Formed by Saint Hremona, the Mariner Federation was intended to be a governing body to provide protection for Mariner races by regulating Imperian demands for tithes and tributes. The Federation's three wings--the Europan Federation, the Asiatican Federation, and the Aprican Federation--employ political negotiators as well as a military force that is touted as neutral and in strict service to Federation conflicts.

Mariner Harpastum Leagues
The game of harpastum was imported by Imperians but changed significantly as they interacted with Mariner races. These races, while excluded from the Gymnasiad, compete in their own leagues and games. Mariners enjoy more options than Imperians do when it comes to playing harpastum as a profession, and there are many celebrity harpastens on every Mariner-occupied planet in the Imperia.

Chos Krømialmiche
Birthed on Aquitania, Chos Krømialmiche is classified as a terrorist organization, and engages in piracy, kidnapping, and violent acts of destruction against the Imperia. Once almost entirely Aquitani, the organization now boasts many more members of varying Mariner races, and continues to grow and gather support.

The nations of Renanim find it difficult to organize to a significant degree, as their very existence is considered a crime punishable by execution. Organizations within individual camps are varied and numerous, but the overarching ones are rare and very secretive.
The Recovery
Many Renanim have dedicated their lives to finding others of their kind in hiding, and bringing them to safe zones, such as Mauretania, Cappadocia, or Pannonia. They run the highest risk of discovery by Imperian forces, and expeditionary members undergo vigorous training in how to resist interrogation. The name, simply "The Recovery," is intended to not sound like the name of an organization at all, and this group is particularly adept at using codes to communicate.

The Matchmakers' Web
Much like the Imperian concept of gemini, Renanim believe two babies who inhale their first breath at the same time are connected cosmically, and are called bashert. Unlike the gemini, the bashert babies are believed to bring bad luck upon their communities if they're kept separated. Specially-trained archivists called shadchanit keep track of the exact birth times of all Renani babies in their community. They communicate these birth times to other shadchanit in hopes of finding and reuniting bashert infants.

Also known as Daggermen, the Sicarii are called so because of the curved daggers they once used to assassinate targets, usually laced with the deadly hemorrhagic toxin sicara poison. Sicarii were tolerated if not outright cheered by other Renanim for a long time, but on the The Night of Bitter Words when some Sicarii assassins killed members of the Senate, support for the group dried up. This opposition to the Sicarii came too late, as this mass assassination led to the Seventeen-Hour War and ultimately the genocide of the Renanim and their Judaean supporters.