In 2070, world governments began to systematically eliminate people groups whom they accused of being "priveliged." Millions perished in the ensuing massacres. Space travel, once a budding curiosity, became a matter of life and death to the few who survived. Refugees fled the Earth on the world's first warp-capable vessel and created humanity's first extraterrestrial civilization, which they named Crescent, after humanity's first terrestrial civilization in the Fertile Crescent.
The survivors weren't the only ones to leave the Earth. Seven men and women, gifted with immortality and immense magical powers, also took to the stars and used their abilities to terraform habitable worlds for humankind. In the years that followed, a mad dash began to colonize these worlds. Empires rose and fell, and civilizations bloomed and collapsed. After centuries of bloody turmoil, three factions rose to the top: the Crescent Empire, the United Nations Security Council, and the Confederation of Independent Systems.
United Nations Security Council, a.k.a. "Terrans"
With all the bastions of freedom brought to heel, the U.N. consolidated its power around the globe and brought all the earth under its command. World leaders gave up their mortal bodies and took on artificial ones, granting them a twisted form of immortality. The rest of Earth's population, however, went in the other direction, as random massacres and environmental decay brought down the average lifespan to around 30. Today, only the elite are allowed to live on Earth, and much of the empire's production goes to sustaining their lavish lifestyle.
But drugs and sex don't help expand an empire, so the U.N. started several (admittedly innovative) programs to build its fleet. They harvested minaral-rich planets, broke down asteroids, and transformed stellar energy to matter. In the end, after centuries of rapid colonization and tireless effort, they created an armada of over 100,000 vessels, ranging from shuttles and starfighters to battleships and super-dreadnoughts.
What infuriated U.N. leaders, however, was the fact that using it would only feed precious resources to their age-old enemy, the Crescent Empire.
The Crescent Empire controls nearly half the galaxy, making it the single largest faction in the known universe. Founded on principles of justice and individual liberty, they are also the most peaceful and stable of the galaxy's three factions. What grabs everyone's attention, though, is their hyper-advanced technology. Advances in automation and artificial intelligence have rendered low-level work practically obsolete. Healthcare is cheap, efficient, and effective, able to prevent and cure almost any condition. Transportation has never been quicker or safer, even with the procurement of commercial teleporters and flying cars.
But you're probably more interested in military technology, and there's a lot to love in that department. Three key technologies revolutionized Crescent warfare: Seed, artificial cells, and true artificial intelligence. Seed is a psycho-sensitive nanomachine that, put simply, is the medium of magic. Think of it as sci-fi fairy dust: anything it touches becomes a viable object of magical interaction. It is useful for telekinesis, alchemy, shapeshifting, construction & destruction, and much more. It can even be automated.
Artificial cells are, as their name implies, microscopic machines that can store the blueprints of an entire design in each and every cell, including procedures for their own recreation. This allows for an unprecedented level of construction ability that far exceeds simple auto-repair. Systems made out of artificial cells can shapeshift into any desired form and rebuild themselves from scratch. It forms the foundation for every piece of military hardware operated by the Crescent military.
True artificial intelligence is created through a combination of mind-mapping and artificial neurons. The resultant A.I. is sentient, and the more advanced systems are sapient. With true A.I. at the helm, the need for actual humans to put their lives on the line dwindles considerably, though the Crescents make a point of putting at least one operator at the helm anyway with absolute override authority.
Confederation of Independent Systems
An alliance of systems not affiliated with any other faction, the C.I.S. is the most chaotic of the three. Some systems are run by pirates, others by pacifists, and everything in between. What binds them all together is their distaste for unified interplanetary government. While individual systems may bicker and fight with each other endlessly, threaten one of them, and the whole alliance comes to the rescue. Their technology varies wildly from planet to planet, but on the whole, they're slightly more advanced than the U.N.S.C.
While Crescent military systems can fulfill pretty much any role you want them to, most are (obviously) designed with certain roles in mind. Most offensive systems fall into one of four categories: blasters, cutters, mass drivers, and missiles. Blasters are energy weapons, most commonly plasma, and are favored for their ballistic properties and energy efficiency. Cutters are beam weapons designed for precision and raw power. There are small, handheld cutters for infantry, and there are huge, dreadnought-grade super-cutters for issuing forth great swaths of destruction. Mass drivers are projectile weapon slung by a magnetic field to a fraction of lightspeed. They are the most devastating weapons in the galaxy behind nukes, and are mainly used when you hate your target so much that you want to wipe it off the face of the universe. Finally, there are missiles. This is a broad term that refers to any self-propelled projectile weapon, but only two kinds of missiles are important: warp missiles and micro missiles. Warp missiles are designed for interstellar conflict, able to strike targets several lightyears away. Micro missiles, on the other hand, can be used effectively by everything from infantry to starships, and are one of the empire's most devastating non-mass-driver weapons. Starships tend to fire them en masse at anything smaller than a frigate, and occasionally wield them against larger vessels in a pinch.
For defensive systems, the Crescent military relies on energy shields, point-defense cutters, and adaptive armor. Starship-grade shields are strong enough to touch a star without breaking and can regenerate from zero to full in under two minutes. Fusion drives and graviton generators make even battleships nimble enough to put starfighters to shame, so dodging weapons fire is a valid tactic.
As for FTL travel, there are not one, not two, but three options to choose from: warp, wormhole, and hyperspace. Warping works by compressing spacetime in front of the ship and expanding it behind the ship. It's hardly glamorous, but its safety and efficiency make it an attractive choice for the average pilot. Wormhole jumping collapses two points in space together, allowing nigh-instantaneous transit between the two points. The total energy costs are the same compared to warping, but the instantaneous travel means the reactor has no time to regenerate energy during transit, limiting the effective range of the jump. Hyperspace jumping opens a rift to another dimension, allowing a vessel to travel at FTL speeds on its impulse drives. This offers the greatest efficiency and second-best travel rate compared to the other two options, but it is far and away the most dangerous, since all kinds of unimaginable horrors live in that dimension. They CAN be fought, and the Crescent military can hurt them and live to tell the tale, but it's not sufficiently advanced to do so routinely or effectively (as its humiliating defeat at the Battle for Aion demonstrated).