Welcome to the Astral Sea
So you've found yourself out here on the Astral Sea. Whether you've ventured out from the only planet you've ever known on purpose or accidentally stowed away on what you thought was a normal "helm-less" galleon and now suddenly found yourself lifted up into the sky; either way, your universe just got a little bit bigger. This pamphlet is designed to give you a quick rundown of what's what and who's who.
A Who's Who...
The wider universe is home to an incredibly diverse population with vast histories and politics, below is a nice starter for the uninitiated of the most major players in the Astral Sea:
Githyanki Empire
For millennia the people who would be come known as the Gith were slaves and servants of the Illithid Mind Flayers, psychic parasites and sinister manipulators. A leader emerged among the Gith and lead them into open rebellion against their oppressors and eventually their freedom was won. The Illithid Inquisition was shattered and the thousands-of-thousands of colony worlds were liberated. However, where there was once order, there was now chaos; the Gith were riven into the war-hawkish Githyanki and the peaceful Githzerai. The Githyanki started an empire of their own, led by Empress Vlaakith I. One pact with the Dragon God Tiamat later and red dragon riding Githyanki became a symbol of destruction and war throughout the cosmos.
The Githyanki spend the vast majority of their lives on the Astral Sea, where no mortal creature ages or dies, only entering a Wildspace to lay their eggs and raise their children. Because of this it is almost impossible to say how old any one Githyanki truly is, let alone say the age of the Empire, but the last Empress to be coronated was Empress Vlaakith CLVII, who has lead her people for at least the last 1000 years, a suspiciously long life even among Githyanki leaders. The Githyanki control enormous swaths of the Astral Sea and prey indiscriminately on anyone who dares be foolish enough to come too close to their territory, knowingly or not. Githyanki warbands are a common peril out on the Silver Sea, even in the farthest throws of the Reach.
Xaryxian Empire
For as long as there have been Elves, there have been elves who have been drawn to the Astral Sea. The descendants of those who first ventured out into the great ardent beyond became the Astral Elves. In particular, the Astral Elves were a people who found a way to draw power from their star, Xaryxis, and greatly empower their magics beyond their material counterparts. Those who lived under the Light of Xaryxis were prosperous, and the Astral Elves shared their prosperity at first, expanding their borders to rival even the Githyanki Empire, but not all that is elvish is undying. The light of the star Xaryxis began to fade after thousands of years of exploitation, forcing the Xaryxian Empire to recede for a time. Many worlds and systems who depended on the Light were abandoned and many more suffered.
Since then, the Astral Elves have become especially cloistered and secretive, blockading the edges of their empire as they have slowly but steadily expanded again. Some say that Xaryxian Empire have found a way to replenish their dying star, and thusly their own power, but all that is known is that one-by-one, worlds farther and farther away from Xaryxis have fallen behind the blockade and nothing is ever heard from them again.
Circle of the Known Spheres
Trade across the Astral Sea is lucrative, add to it the natural mortal desire to explore and expand, and you've got all the incentive you need for countless creatures to hop on a Spelljamming Ship and venture out into the great unknown. With each venture there is risk, as well as alien contact. When the leaders of nations of Oerth (Greyhawk), Toril (Forgotten Realms), and Krynn (Dragonlance) learned of threats and dangers presented by the creatures living throughout the Astral Sea, and especially of Xaryxis' penchant for expansionism, they forged a military and trade alliance and as a single front negotiated a hard-fought but delicate agreement with the Xaryxian Empire. Worlds and systems under the protection of the Circle are promised to be safe from the Xaryxian blockade, and in exchange the Circle's assist in maintaining the blockade and prevent over-zealous explorers, pirates, and malefactors from crossing into Xarxyian systems.
Outside of being a treaty kept secret from the vast majority of its signatories' subjects, the Alliance represents an assortment of trade agreements and regulations between its member systems, all enforced by the single largest known spelljamming navy, comprised of citizens of all of its protected worlds. Though its forces are arguably spread thin patrolling the Xaryxian border.
The Rock of Bral
Where there are rules, there are those who'd break them, and they all live on the Rock. The Rock of Bral is the most well known destination out in all of the Astral Sea; everything that matters goes through the Rock and if doesn't goes through the Rock, it doesn't matter. Pirates, ne'er-do-wells, legitimate businessmen, and adventure-seeking sailors alike all make their homes on the Rock of Bral. Once a Torillian prison colony, then a pirate refuge, now the Rock has become the hub of all life beyond the Alliance. In a Wildspace known as Fringespace, the Rock sits at the heart of the Reach, the corner of the Astral Sea outside of the Githyanki, Xaryxian, and Alliance influences. The Rock is ruled by a Prince, not a king, as the title would clash too sharply with its founder motto, "no kings, no masters," and it operates under its own set of rules.
Everyone wants the Rock to themselves, but no one faction is strong enough to fight off all the others involved, and the elite and powerful who call the Rock home take advantage of that fact with every deal their strike and every "legitimate salvage" they plausibly deny plundering.
Dowhari Creche Cabal & the Mercane Agency
The Dowhari Creche Cabal, or the "Creche" is the most prominent financial institution this side of the multiverse; if they had fingers, the Dowhari would have one of them in every pot from here to Sigil. The Creche operate as a centralized bank, as universal creditors, and as reliable merchants with branches all over the Astral Sea. The Mercane Agency on the other hand is elusive. If you ever find yourself dealing with one of the Mercane's Agents, it will be because they chose to find you, and they don't deal in the mundane. Advanced technology, secret magics, and ancient curios are the only objects that the Agency deal in. It is said that spelljammers are everywhere, but not by some miracle of convergent arcana, but because the Mercane couldn't help but sell one to every living creature curious enough to turn its head up and wonder about the stars. Rumor has it that the Mercane are even the inventors of the modern spelljamming helm, though there are some other theories, but no one Mercane would ever speak to you long enough to say so one way or another.
The Salus Priory
The power of the gods is undeniable, but the gods' reliance on mortal worshipers strikes a befuddling juxtaposition. While it might be easier for terrestrial creatures to ignore the power mortals hold over the gods, out in the Astral Sea the faceless, stone corpses of dead gods float all about the void, inviting inquisitive minds to wonder by what mechanism did these all-powerful being meet their fates. It doesn't help that the gods themselves do little to answer these doubts, instead dismissing the questions entirely or, worse still, demanding blind loyalty from their followers under threat of death.
For some, the answer is a newer faith, the Salus Priory, or the Priory of the Sacred Gift. Priors leading this faith simply pose, "if the gods themselves require something of you, you must possess something of value," and they answer that it must be the "sacred gift of life." The Priory's messages focus on a community's duty to foster the power of each of its individuals, and their mantras stress the connectedness of all life with that "one being" becoming more powerful when each individual is at their most powerful. Priors speak on salvation coming through the oneness, and that through oneness all individuals can be understood and that the will of the one is more powerful than any pantheon of gods.
This Priory's following isn't necessarily very large, but its teachings of self-actualization and ethical-egoism speaks quite effectively to the elite and so the Priory has found itself quite well funded, recently even inheriting a rather large plot in the Rock's Temple District. Critics of the Priory are quick to point to its wealth, but its priors and acolytes work exceptionally visibly with the poor and down-trodden, making it difficult for such criticisms to stick in the public consciousness. What's most frustrating to the more traditional theistic orders, members of the priory have consistently demonstrated exceptional power, both in healing and in other magical supports, and have taken to charging fractions of the nominal gold cost for such services, if they charge at for them at all.
What has happened...
This is where things get spicy. They say that its a blessing to live through boring times, and if that's true, you are most definitely not blessed.
The Death of the Emperor
In an uncharacteristic display, envoys from the Xaryxian Empire spread the news far and wide: the Empire and all her allies are to enter a period of mourning, for the Emperor Xavan has passed. The throne is set to be inherited by his twin children, Prince Xeleth and Princess Xedalli, following all the rites and customs for mourning. The arrangement of twin Emperors is not unprecedented in Xaryxian society, but that fact does little to quell the concerns of the Astral Sea's larger population. Little is known of the emperors-to-be outside of the Empire itself, but one can hope that the change this promises to bring will benefit all.
The Githyanki Civil War
Recent events on Toril, in a city named Baldur's Gate, have left the Illithid Inquisition in tatters, and sparked a civil war between Githyanki. The civil war has grown to be massive, but is quite well contained within Githyanki territory. Many systems that used to be controlled by the Githyanki have been abandoned as fleets and clans have fallen back into the depths of their most centralized worlds to rally behind their chosen banners. This massive retreat in particular has proven to be extremely fruitful for pirates and treasure hunters, far more so than in any other time in known history -- the Githyanki Empire was built upon the bones of the Illithid, and their empire was built on something even older. Tombs, artifacts, lost worlds and civilizations, for the first time in millennia are accessible from under the retreating leathery boot of the Githyanki. There be dragons, and there be gold for those brave or curious enough to take it -- somehow, even the junk has buyers everywhere.
The Pirate Prince
In a touch older news, but still quite relevant as you are most likely headed to the Rock right now, the Prince Andru of the Rock of Bral has been in power for almost 7 years. His rule has been both ruthless and pragmatic, to the dismay of those who would have taken advantage of a weaker or less capable leader. Prince Andru however, is the younger son of his father, Prince Frun. When Prnce Frun passed 7 years ago, the crown fell to Andru's older brother, Calar. Calar and Frun were cut from the same cloth, and many of the powers-that-be on the Rock enjoyed Frun's rule, as he most often left policy decisions to those with vested interests in them, and those same elite surely expected to enjoy Calar's rule as well. However, Calar was not long for this world. Six days after his coronation, Prince Calar's body was found floating just outside the Rock's atmosphere. The throne then fell to Andru, who's first acts were swift and effective -- the regicides were found and publicly executed the next day. Though many are suspicious of how quickly Prince Andru was able to discover and capture the culprits, in the years since, Prince Andru has demonstrated similar feats of impossible awareness and preparedness against his foes, earning him the title of the Whispered Prince, as the superstitious have taken to avoiding speaking of him in more than hushed tones.