First Order–Resistance war

"The war is just beginning..."

- Jedi Master Luke Skywalker to Kylo Ren

The war between the First Order and the Resistance began upon the escalation of the cold war into full scale open warfare between the two factions for control over the galaxy. While the First Order, the successor to the fallen Galactic Empire, sought to conquer the known galaxy from the Unknown Regions, the Resistance sought to preserve the democracy restored by the shattered New Republic after their struggle against the Empire thirty years prior.

The war officially began in the year 34 ABY when the First Order fired its planet-sized superweapon on Starkiller Base on the Republic capital of Hosnian Prime, destroying the Hosnian system, and with it the Galactic Senate and New Republic Starfleet. Shortly afterwards, the Resistance launched an assault on the stronghold, resulting in its destruction and the beginning of open warfare.

Prelude
"When we look back upon the war against the Empire—upon the billions of lives lost—sometimes it seems as though nothing could ever have been worth the terrible price we paid. But when we think of those people who perished in the conflict, let us remember that they died for justice. For liberty. For the extraordinary peace we now enjoy. This is what we fought for."

- Senator Tai-Lin Garr

At the end of the Clone Wars in 19 BBY, Supreme Chancellor Sheev Palpatine, who was secretly in fact the Dark Lord of the Sith Darth Sidious, declared himself Emperor and reorganized the democratic Galactic Republic, which had governed the galaxy for a millennium, into the first Galactic Empire, replacing the Galactic Senate with the Imperial Senate. The Emperor had his new apprentice, the fallen Jedi Knight Anakin Skywalker, now Darth Vader, oversee the deaths of the remaining Separatist leaders and the purging of the remaining Jedi that had survived Order 66 and the march on the Jedi Temple, leaving the Jedi Order destroyed.

Despite the promises of security and order that the Old Republic had failed to provide, the Empire eventually faced early rebellion that came to consolidate into the Alliance to Restore the Republic. The Rebel Alliance and the Empire soon came into conflict in the form of the Galactic Civil War, with the former securing a major victory at the Battle of Yavin where the Death Star was destroyed. Four years later, in 4 ABY, the Emperor used himself and the second Death Star as bait to lure out the Alliance Fleet and Luke Skywalker, a new age Jedi and son of Darth Vader whom the Emperor sought to replace. However, at the Battle of Endor, Vader turned on the Emperor and killed him, saving his son and redeeming himself, fulfilling the prophecy of the Chosen One and leaving the Sith extinct. Anakin died in his son's arms moments later, though Luke was able to escape as the second Death Star exploded. As the Rebel Alliance transformed into the New Republic and restored the Galactic Senate, Luke set out on his path to restore the Jedi way to the galaxy.

The war between the New Republic and the Empire culminated at the Battle of Jakku one year later in 5 ABY. Though the Republic was victorious in battle, many select Imperial officers, nobles, and soldiers were able to retreat into the Unknown Regions as part of a secret Contingency plan devised by the late Emperor to rebuild the Empire, though the plot to destroy Jakku and thus cripple both the Old Empire and the New Republic had failed. Imperial remnants that continued to persist in the known galaxy agreed to the Imperial Instruments of Surrender and signed the Galactic Concordance with the New Republic.

The cold war
"We're on the brink of war again—one we may not survive."

- General Leia Organa

In the aftermath of the war, the New Republic made an earnest effort to rebuild what was lost over the course of the five year conflict, also taking steps to ensure that nothing on that scale would ever happen again. The Galactic Senate passed the Military Disarmament Act, heavily demilitarizing the New Republic military and instead pressuring individual planets and star systems to rely on their local planetary defense forces. Despite the subsidized military, the New Republic was still faced with threats sizable in proportion. Choosing to ignore the stipulations of the Galactic Concordance, some united remnants of the Empire refused to yield, culminating in a cold war between the New Republic and Empire.

Over the years, Imperial factions and remnants would briefly inhabit a wing of Republic politics while, hidden away in the Unknown Regions, other Imperial loyalists plotted their return to power, forming the First Order. The First Order colonized planets in the Unknown Regions and rapidly expanded their military power, rebuilding Imperial fleets and mobilizing stormtrooper forces within its armies, with the hopes of restoring Imperial glory. Tensions between Imperial sympathizers, many of whom were Centrists, and Republic loyalists, many of whom were Populists, would eventually reach an all time high that would cause many former Imperials to secede from the Republic and join with a growing First Order. While the notion was supported by many, others feared that, without Republic oversight, former Imperials would return to the draconian ways of the fallen Empire.

Senator Leia Organa, the sister of Luke Skywalker, petitioned the Galactic Senate and Republic Command to take action, but found herself sidelined by the political realm of the New Republic, especially after the revelation that Darth Vader was in fact her and Luke's father in a political scandal between the Centrists and the Populists. With the Republic seeking to avoid another galactic war at all costs and not viewing the First Order as a credible threat to galactic peace and freedom, Princess Leia stepped down from her political office in 28 ABY and formed the breakaway Resistance, where she held the rank of General. Though not officially supported by the Republic, the Resistance was tolerated, and secretly some within the Galactic Senate assisted in funding the private military force.

A declaration of war
"Today is the end of the Republic. The end of a regime that acquiesces to disorder. At this very moment in a system far from here, the New Republic lies to the galaxy while secretly supporting the treachery of the loathsome Resistance. This fierce machine which you have built, upon which we stand, will bring an end to the Senate, to their cherished fleet. All remaining systems will bow to the First Order and will remember this as the last day of the Republic!"

- General Armitage Hux

Conflict began between the First Order and the Resistance while the government of the New Republic under Chancellor Lanever Villecham focused more on trade relations with neutral regions of the galaxy such as the Trans-Hydian Borderlands, unaware of the danger that they were in. In 34 ABY, the First Order, long hidden away in the shadows of the Unknown Regions, used its superweapon built into Starkiller Base to target and destroy the Hosnian system, where the Republic capital of Hosnian Prime was located, resulting in the Hosnian Cataclysm. The Galactic Senate and Defense Fleet were completely obliterated, and the Republic was shattered. In response, the Resistance retaliated by launching a successful assault on Starkiller Base, destroying the planetary superweapon and dealing a significant blow to the new war machine engineered by the First Order.

Nevertheless, the First Order, still at strength, began mobilizing to launch its campaign of conquest while the Resistance began its evacuation from their base on D'Qar in order to continue their mission in combating the First Order and preserving the democracy, freedom, and justice in the galaxy that the New Republic and Rebel Alliance had restored. Open warfare had begun. But there was hope: General Organa sent the Force-sensitive scavenger Rey to the first Jedi temple on Ahch-To, where her brother, Luke Skywalker, the last Jedi, resided in self-exile after the destruction of his Jedi students some years earlier at the hands of Kylo Ren, the master of the Knights of Ren, student to Supreme Leader Snoke, warrior of the First Order, and son of Leia Organa and Han Solo.

Behind the scenes
Despite not having an official name, the First Order–Resistance war made its first appearance in Star Wars: Episode VII The Force Awakens and continues in Star Wars: Episode VIII The Last Jedi.

Non-canon appearances

 * LEGO Star Wars: The Force Awakens
 * Star Tours: The Adventures Continue