History of the universe

Areth's last invasion started long before the infamous events of Nightfall which eventually led to The Reckoning. It started when Areth tricked the humans of Amet into worshipping him as a sun god and had them conquer most of Twilight World and culminated when his priesthood performed a Ritual of Binding to bind their Great Temple to the sun effectively tidal locking the world and creating a portal directly to Hell. Half the world got burned in the harsh permanent heat of the sun, the other half was plunged into darkness and cold. Nightfall was ended when The Travelers, intent on saving their world and restoring its balance, defeated Areth on Unknown during The Reckoning. 

For millennia travel through the Void to other worlds was only the exclusive domain of skilled but reckless wizards and other powerful beings, until Zabrina, an unassuming Tiefling journeywoman of the Universitas, invented the Spelljammers. Despite attempts by several parties to monopolize them, Spelljammers spread through the universe like wildfire and there are now several large scale manufacturers of Spelljammers and numerous backyard artificers and inventors working on their own pirated designs. 

Immediately when the Spelljammers was invented by Zabrina while she was employed by Ego Ultd. the corporation did everything in its power to keep a tight hold on the invention, sparing not even its creator. When the Tritons got their hands on the blueprints the corporation did not hesitate to defend its patent by any means necessary culminating in a plot to abduct the triton's queen. When the plot came to light the Tritons declared war on Ego Ultd.. After several initial skirmishes ended in the destruction of a large portion of both faction's limited spelljammer fleet the war went cold until the Minotaur joined the war, in exchange for access to the spelljammer plans, leading to the formation of the Trimino Combine. With the manufacturing power of 4 worlds pitted against them and hostilities drawing ever close to Twilight World Ego Ultd. was forced to seek terms resulting in the 3 races signing a treaty promising to limit Spelljammer construction to the three of time, forming the The Spelljammer Cartel. 

For decades after the invention of the spelljammer its widespread use was limited to first Ego Ultd. and later The Spelljammer Cartel. It wasn't until the Giff got their hands on a prototype and started producing their own cannon ships that the superpowers' monopoly was threatened and when threats failed to deter the Giff from assert their Itoan given right to explore the void, the The Spelljammer Cartel in an echo of the first interstellar war launched the first strike in what would become the first Cartel - Giff war. Arrogant in their monopoly the Cartel thought they could destroy the tiny Giff fleet with a single decisive strike, however their simple catapults and ballista's proved no match against the Giff's gunpowder cannons and the Cartel fleet took horrendous losses. What followed was a meatgrinder war with the Cartel attempting to leverage their greater manpower and manufacturing capability by launching ship after ship, and their crews, towards Powder World only for them to be shot to smithereens by the Giff's cannons. Both sides took horrible losses until popular support for the war started to dwindle in the Trimino Combine. There was never an official peace treaty signed between the The Spelljammer Cartel and the Giff but hostilities ended and with the Giff's victory another interstellar power was born in the Core. Not long after more rogue inventors started creating their own Spelljammers forcing the The Spelljammer Cartel to start selling Spelljammers outside their own organizations, all this new access sparking the Age of Connection. 

It took some time for Spelljammerss to evolve from small exploration and transportation crafts to the modern ships we know today, capable of moving dozens or even thousands of people through the Void. With this increase in capacity the peoples of the Core for the first time began to truly look outside their backyard and into the Wildspace beyond. As the first explorers and adventurers began to return with stories of bountiful planets and moons ready to be taken, every race, disaffected minority, religious cult and ambitious corporation staked their claims, bought or built the largest Spelljammers ship they could afford, and are aiming to set off into the void to colonize this new wild frontier.