The Hydrin Clans are a loose confederation of tribes that wander the galaxy in a community of scavenged ships.
Most who are familiar with the Hydrin Clans think that they originated in Hydra Sector (because of their name). The Elders have removed the details of their homeworld from the Clan Sagas, a highly allegorical series of poems that relate the history of the Clans. According to the Clan Sagas, they Hydrin Clans are all that is left of their homeworld, which was destroyed after being betrayed by their allies against something called the Dragon. The Hydrin Sagas state that they slew the Dragon and that the traitors suffered a fate worse than death, but that the Clans had to leave their homeworld behind forever.
Although the Clans originally consisted only of refugees from the same planet, they are known to accept vagabonds, refugees, and drifters- even alien ones- as long as they swear loyalty to the Clans and receive their mark. The Hydrin Clans are loyal only to themselves. Betrayal is the direst crime in the Clans.
The Hydrin Clans survive by being professional mercenaries. They are not just warriors for hire, but also engineers, medics, mechanics, and other services. However, Hydrin will not fight other Hydrin, even if they are hired by opposing forces. The Clans will quit the field before they engage one another.
The Clans have spent the last hundred and fifty years wandering Atragon Sector, serving as foils in the unending conflict between the sector's two major polities: the Arcanian League and the Technocratic Unions of Runaris. These two powers also have enough infighting between their members that they sometimes hire the Hydrin Clans in their internal struggles as well.
While outsiders consider the Hydrin to be barbarians, they are actually a fully modern Tech Level 4 civilization. Their code of honor is also far more civil than many of the so-called "enlightened" worlds of the Arcanian League. The Clans also pride themselves on their reputation for getting the job done, and on their reputation for taking revenge on those who attempt to set them up or manipulate their code.
I've used the Hydrin Clans as a great way to start off a campaign. Players from any walk of life could have joined the Clans, and their work as mercenaries can give PCs lots of opportunities to explore a sandbox, plus give them a base to come back to between excursions. Players who want to be a member should take Culture/Hydrin among their starting skills. Any background, class, and even race is permissible within the Clans.
Two examples of Clans within the Hydrin:
House Raideen- The Raideen are one of the oldest Clans, claiming that their ancestors were among those who organized the exodus from the original Hydrin homeworld. They have a great deal of hereditary wealth and a strong warrior tradition. Elite soldiers of House Raideen, called Danes, are among the fiercest warriors in the fleet.
The Raideen have taken a sacred bird of their homeworld as a totem. Raideen nobles often dress in feathers and their armor is often decorated with avian motifs. Among the Clans ships is an aviary that contains species of birds not found anywhere else in the galaxy. (The Elders say many are species rescued from the original homeworld.)
Although there are not many psychics in House Raideen, they have a strong tradition of precognitives among their number. The Hydrin see psychic abilities as a form of divine sorcery, and much of their psychic training is clothed in superstition. Many Raideen psychics resemble vagabond witches and soothsayers like in the stories of old.
House Sasara- This Clan is composed entirely of ssath (detailed in the SWN core rules.) This particular group of ssath were feral until the Hydrin encountered them. Impressing the Hydrin psyche upon themselves, they were lifted out of their hereditary madness. They took the mark of the Clans and became a Clan unto their own right. Sasara is a small Clan and mostly they keep out of Clan politics. They have a soft spot for alien vagabonds and refugees who seek solace among the Clans. They boast more psychics than any of the other Clans.
The Sasara have a strong tradition of hospitality. When they entertain guests of a non-human species, they often assume the guest's general form as a gesture of welcome and respect.
Artwork by Frank Frazetta