Cataclysm
People choose to seek a new life amongst the stars. Earth is overcrowded and faces environmental collapse. Resources are strained and everyday life is controlled by uncaring megacorporations.
Exodus
The waves of settlement are propelled forth by faster-than-light ships owned by governments and private industry.
Communities
Ships and settlements are bound by allegiance to various groups - various blocks of Earth governments, corporations, guilds. etc.
Iron
The Ironsworn bind their honor to iron blades, whether swords or knives. Aboard a starship, where stray gunfire can destroy fragile equipment or pierce hulls, the brutal practicality of a sword makes for a useful weapon. A few also favor the silent efficiency of a blade for infiltration or espionage. Most importantly, when the Ironsworn swear a vow upon a sword, they bind their commitment to the metal. If they forsake a vow, that iron must be abandoned. To be Ironsworn without a blade is to be disgraced.
Laws
Much of the settled domains are a lawless frontier. Criminal factions and corrupt leaders often hold sway. Powers rise and fall in the Forge, so any authority is fleeting. In the end, we must fend for ourselves. A few communities are bastions of successful autonomy, but many are corrupted or preyed upon by petty despots, criminals, and raiders.
Religion
Our faith is as diverse as our people. Many have no religion, or offer an occasional prayer out of habit. Others pay homage to the gods of our forebears as a way of connecting to their roots. Some idealize the natural order of the universe, and see the divine in the gravitational dance of stars or the complex mechanisms of a planetary ecosystem.
Magic
Magic does not exist. Some look to superstition and age-old traditions for comfort in this unforgiving galaxy. But that is foolishness. What some call magic is simply a product of technologies or natural forces we aren’t yet equipped to understand.
Communications
In settled domains, a network of data hubs called the Weave allow near-instantaneous communication and data-sharing between ships and outposts. Because of their importance, Weave hubs are often targets for sabotage, and communication blackouts are not uncommon. Beyond the most populous sectors, travelers and outposts are still commonly isolated and entirely off the grid.
Medicine
To help offset a scarcity of medical supplies and knowledge, the resourceful technicians we call riggers create basic organ and limb replacements. Our medical technologies and expertise is co-opted by the privileged and powerful. For most, advanced medical care is out of reach. When someone suffers a grievous injury, they’ll often turn to a rigger for a makeshift mechanical solution.
AI
Machine intelligence is not commonplace but many people have some experience with AI, either in ships or corporate owned robots.
War
Resources are too precious to support organized fighting forces or advanced weaponry. Weapons are simple and cheap. Starships are often cobbled together from salvage. Most communities rely on ragtag bands of poorly equipped conscripts or volunteers to defend their holdings, and raiders prowl in search of easy prey.
Lifeforms
This is a perilous and often inhospitable galaxy but life finds a way - either naturally or through genetic engineering.
Precursors
Over eons, a vast number of civilizations rose and fell within the galaxy. Today, the folk we call grubs—scavenger crews and audacious explorers—delve into the mysterious monuments and ruins of those ancient beings. Incomprehensible technologies, inexorable time, and the strange energies of the Forge have corrupted the vaults of the precursors. Despite the perils, grubs scour those places for useful resources and discoveries. But some secrets are best left buried, and many have been lost to the forsaken depths of the vaults.
Horrors
Put enough alcohol in a spacer, and they’ll tell you stories of ghost ships crewed by vengeful undead. It’s nonsense. Within the galaxy, space and time are as mutable and unstable as a flooding river. When reality can’t be trusted, we are bound to encounter unsettling phenomenon.
Taken from Ironsworn Starforged by Shawn Tomkin