Space Travel

No one knows exactly which civilization first achieved spaceflight, but by the beginning of the modern era, nearly every world had some form of interplanetary travel. For some, this was purely magical: powerful spells or artifacts, or quick jaunts through other planes of existence allowed travelers access to their intended world. Yet for others, the airless void of space was just another sea to be crossed, which they did in a variety of craft, from magical to mechanical and from biological to divine.
As technology improved, travel time between worlds dropped from months and years to days, and the optimal routes between planets became crowded with spacecraft. Yet even in this new age of space flight, voyages beyond the solar system remained rare; traveling to even the nearest star at conventional speeds would take generations. While a few starships had drives capable of circumventing this obstacle, all relied on extremely expensive magical technology, often controlled by churches or other organizations. From Magogian Helldrives to Mournite Shadow-Engines engines to the prayer-fueled cores of Brisingelion Cathedralships, most of these technologies not only took the ship through other planes but also operated with direct divine assistance, and thus always came with a hefty price. While other drives had been theorized—drives that could fold space, create stable wormholes, or otherwise bend the rules of physics— the worlds of Edrazion had never managed to build them.
Then, 3 years after the end of the Gap, the Signal went out. Some worlds received it as a broadcast; to others it came in the dreams of inventors or lunatics, or etched into floors by malfunctioning assembly robots. Still others dug it from the innards of crashed space probes, found it carved on monoliths in city centers, or heard it blared from the sky by entities within wheels of flame. Regardless of the mechanism, at the same instant, thousands of cultures across the Material Plane received the same information: blueprints for a new type of starship drive— one capable of cheaply and efficiently shortening the distance between stars.
Though some scholars argue that every mortal culture received this information, many recipients were never aware of it or able to capitalize on it. In some cases, cultures weren’t technologically advanced enough to interpret the information— explorers have even uncovered these designs painted on cave walls by uncomprehending paleolithic cultures. In other cases, the information was lost due to a simple accident, as when an inventor blessed with the information fell out a window before he could share it.
Immediately following the Signal, the newly empowered deity, Lesu the Star Walker revealed its new form to the galaxy, claiming to have granted the knowledge as a blessing to its mortal children. Formerly three minor consort gods of machines, invention, and stellar mysteries - they were now integrated into the living deity Lesu as a single entity. The divine collective claimed to have peered through the substrata of reality and discovered a previously unknown plane of existence. Called the Drift, this plane could be reached only via technology—not magic— and would allow mortals to cheaply and easily travel between points anywhere in the galaxy. In granting this discovery to the galaxy, Lesu became perhaps the most powerful entity in the multiverse overnight: the supreme deity of all interstellar travel.
Like earlier interstellar drives, Drift engines operate by jumping to another plane of existence and then back to a different point on the Material Plane, thus never actually running up against the hard limit presented by the speed of light. In the past, that had meant using powerful magic and traveling to places like the Empyrean Firmament, the Pit, the Elemental Chaos, or the Faewyld—places inhabited by creatures and gods with sometimes inconvenient attitudes and appetites. The Drift, on the other hand, is a different type of dimension: a void of swirling color without substance, a mostly empty place of mutable laws, thought by some to be the quantum foam underlying all creation. While magic still functions inside the Drift, only technology can pierce the membrane between it and the rest of reality, which, combined with Lesu’s role as gatekeeper, keeps any other deities or organizations from monopolizing the place.
While even most skeptics and members of other religions are forced to admit that Lesu has appeared to make good on its egalitarian offer to maintain cheap and easy interstellar travel for everyone, use of the Drift does come with a catch. Every time a Drift engine is used, a tiny portion of a random plane is torn from its home and added to the Drift, set to float there for eternity. The farther the jump, the larger the chunk of material, which sometimes appears near the jumping ship, adding an element of risk: you never know when a long jump might tear away a chunk of the Pit and leave you flying through a cloud of furious devils. Even those making safely measured jumps might encounter strange beasts trapped there by previous travels. Why the technology involves this side effect is unknown, though some conspiracy theorists believe that the ever-increasing size of the Drift—and the corresponding shrinking of the other planes of existence—is part of an inscrutable power play by Lesu itself.