Warning: Spoilers for the series finale of Star Wars Rebels
Star Wars Rebels had some major crossovers and tie-ins with some other Star Wars movies, namely Rogue One, but at the end of the day it was mostly a stand-alone story. Instead of the series finale featuring the Battle of Scarif or bringing in a major character, it instead turned back to its own roots as the Ghost Crew and friends battle for the freedom of Lothal. Even so, the conclusion of the show could have implications that shape the face of the Star Wars franchise for years to come.
Coming to a close with some shocking twists, Rebels saw Ezra calling the Purgil (hyperspace whales) to come and jump him and Thrawn to a mysterious location, followed by the reveal that Ahsoka and Sabine will team up to go find them, teasing what many hope is the next Star Wars animated show.
It's not clear where Ezra a Thrawn went, but the Unknown Regions are the most logical explanation. After all, Star Wars has been building the region up in various forms of canon media since the franchise was revived with The Force Awakens. It's where Thrawn comes from, where the Empire became the First Order, and also where Snoke comes from. With some additional historical significance in non-canon Legends continuity, it only makes sense that the franchise would find its future by leaving the known galaxy and funding something untouched by previous events in the saga.
What Are the Unknown Regions?
The Unknown Regions is a fairly nebulous term that could refer to a specific area or just any region of uncharted space, as suggested by the word "unknown." Despite the fact that they're shrouded in mystery, we have slowly learned a few details about them.
First, part of the reason they're unknown is travel to and from them can treacherous. As explained by Han Solo, "Traveling through hyperspace ain't like dusting crops, boy! Without precise calculations, we could fly right through a star or bounce too close to a supernova and that'd end your trip real quick, wouldn't it?" Most ships in the Star Wars galaxy get around by following pre-established hyperspace routes certifying safe passage, but there are no well-known routes charting navigation through to the Unknown Regions. It's too dangerous to just jump straight through because the expanse between is full of space debris and other anomalies, but it's also devoid of easy landmarks or habitable planets at which to stop, making it nearly impossible to chart a proper route through at sublight speed.
Nevertheless, it's not entirely impossible to traverse the expanse, as it has been done by some, such as Thrawn, who hails from the Chiss Ascendency in the Unknown Regions. The Chiss were concerned about the existence of a massive threat within the Unknown Regions, so they tasked Thrawn with infiltrating the Galactic Empire to determine if they were a suitable ally to repel this threat.
Curious about the Unknown Regions himself, Palpatine gave Thrawn a position within the Imperial Navy and even leaned on him to chart routes back into the Unknown Regions. Palpatine had sensed a dark energy coming from outside the known galaxy, and believed it could be the very source of the dark side of the Force. He died before he could complete this investigation himself, but he was able to establish a number of research outposts in the Unknown Regions and instructed his top Imperial officers to retreat there after the Battle of Jakku.
In the Unknown Regions, the Imperial Remnant once again began to grow, joining with the forces Palpatine had sent ahead, but they were unprepared for a number of the threats that they encountered there, eventually turning to Snoke, who, like Palpatine before him, used his knowledge of the dark side of the Force to shepherd the Empire as it grew into the First Order, becoming the Supreme Leader, and eventually returning to the known galaxy to reclaim what the Empire had lost.
In the old Legends continuity, the threat encountered by the Chiss was the Yuuzhan Vong. The Vong would eventually go to war against the New Republic and reborn Jedi Order in a conflict that would ultimately be bloodier than the Galactic Civil War between the Empire and the Rebellion. Outside of the similar story with the mysterious threat to the Chiss, there's no indication that the Vong will show up in new canon, but it is interesting to note that Dave Filoni had plans to incorporate them (and possibly Thrawn) into one of the canceled seasons of The Clone Wars.
The Unknown Regions Are the Future of Star Wars
Star Wars is about to run into a problem. The new movies have all been smash hits at the box office, and received mostly positive reviews, but the franchise is starting to run out of runway. The timeline of all current canon material stretches from The Phantom Menace all the way to The Last Jedi, stretching nearly 70 years, with all canon movies, TV shows, games, books, and comics taking place in this timeline. There's lot of room to play with, but it's hard to escape the established eras of the Clone Wars, the Galactic Civil War, and the war against the First Order. It's possible to tell stories not directly related to those, but it's hard to avoid some of the same trappings we've seen in every movie but The Phantom Menace: stormtroopers and Star Destroyers.
Fortunately, the franchise is finally breaking out to tell stories separate from the Skywalker saga with Rian Johnson's trilogy and Benioff & Weiss' series, but in order to stay fresh, Star Wars will need to seek new sandboxes, meaning either jumping outside that known 70 year span, or going to a location so far from known events that it offers a nearly blank slate. They're unlikely to jump into the future since that could impact the viability of sequels to the sequel trilogy (something it's hard to imagine them passing up down the road, with a popular young cast already in place). That means the two best options are more prequels or going to the Unknown Regions.
Interesting enough, the next animated series is already poised to venture outside of the known galaxy. We know Ezra and Thrawn are alive, but we don't know where they are. However, if Ezra is unable to find his own way home, it only makes sense that the Purgil took them to the Unknown Regions or a similarly inaccessible region of the galaxy. This gives Dave Filoni the freedom to take Sabine and Ahsoka and tell stories with a greater level of freedom since their every move won't be met with questions of how it'll impact known events, or concerns of breaking continuity.
It may be a surprising transition for fans used to the more familiar trappings of the eras Star Wars fans know and love, but in order to continue to thrive as a franchise, Star Wars needs to take a page from Kylo Ren's playbook and let the past die. Besides, a few movies or TV shows in the Unknown Regions and the introduction of the Yuuzhan Vong opens up the potential for a pretty crazy trilogy in X, XI, and XII down the road, bringing back Rey, Finn, Poe, and Rose against a non-Imperial or First Order threat.
