Coaxium, also referred to as Corellian hyperfuel or simply hyperfuel, represented a scarce form of hypermatter and a costly type of starship fuel that was extracted from the planet Kessel.
In its natural, unrefined state, coaxium was an extremely unstable and highly explosive form of hypermatter. It necessitated refinement to achieve the stability required for storage at ambient temperatures. Even after refinement, coaxium demanded careful handling due to its explosive nature. Upon extraction, unrefined coaxium would gradually become unstable, changing to a red color before detonating violently if not properly stored within a temperature-controlled environment. A refinery for coaxium existed on the desert planet of Savareen. A quantity of 100 kilograms of the refined substance held a value of approximately 60 million credits.
The hyperdrive reaction chamber of a starship featured a coaxium coating. When energized, this coating facilitated the vessel's travel through hyperspace. Coaxium's potency as a fuel was such that even a small quantity could power an entire fleet of starships. This characteristic rendered it exceptionally valuable and highly sought after by numerous entities. The Galactic Empire undertook the transportation of large coaxium shipments under stringent security protocols, aiming to establish complete dominance over the substance's production.
Insights into purrgil behavior and the properties of the gas Clouzon-36 led scientists to the understanding that coaxium naturally forms in locations with potent interstellar energy, such as Kessel.
During the era of the Galactic Empire, coaxium was a precious material coveted by the Empire and diverse criminal syndicates, including the White Worms, the Pyke Syndicate, and Crimson Dawn.
Thirteen years before the Battle of Yavin, a young Han managed to secure a limited quantity of coaxium. He and his childhood companion, Qi'ra, attempted to use it as a bargaining tool to escape Corellia. This effort was only partially successful, as Han managed to secure his own departure, while Qi'ra was apprehended at the spaceport. Three years later, Solo found himself entangled in a plot to pilfer a shipment of the valuable fuel from a 20-T Railcrawler conveyex transport on Vandor for Dryden Vos and Crimson Dawn. Due to the intervention of Enfys Nest and her Cloud-Riders, Solo opted to release the tethers securing the coaxium rather than adhere to Tobias Beckett's instruction to fly directly into a mountainside. The Cloud-Riders' swoops proved insufficient to support the container's weight, forcing them to release it, resulting in a substantial explosion that caused the mountainside to collapse.
Subsequently, Solo, accompanied by Qi'ra, Lando Calrissian, the Wookiee Chewbacca, and L3-37, executed the Kessel Run to acquire unrefined coaxium from the Pykes and deliver it to Vos as compensation for their previous failures. This time, Solo achieved success, transporting the shipment to Savareen for refinement. He and his allies were soon confronted by the Cloud-Riders, who revealed Crimson Dawn's scheme to utilize the coaxium to inflict widespread destruction across the galaxy.
In a move to deceive Crimson Dawn, Solo provided Beckett with misleading information, anticipating that Beckett would betray him to Vos. He claimed he would be delivering two crates filled with counterfeit coaxium, while in reality, he was transporting the genuine shipment. Both Beckett and Vos were deceived by his ploy, as the Crimson Dawn enforcers attempted to ambush the Cloud-Riders, only to be outmaneuvered by decoys and empty crates before being defeated. Soon after, Beckett took Chewbacca as a hostage, holding him at gunpoint to carry the coaxium off Vos's yacht, but Solo quickly caught up to him and killed Beckett. Following this, he entrusted the coaxium to the Cloud-Riders to support their burgeoning rebellion. After declining Enfys's invitation to join their ranks, she gifted him a single vial of coaxium, which he employed in a sabacc game against Calrissian, ultimately winning ownership of the Millennium Falcon.
Some time after the Battle of Yavin, the MC80 Star Cruiser Aurora Flare was transporting a significant quantity of coaxium from the Redhurne system. Upon receiving news of king Lee-Char's assassination, the Aurora Flare crashed into an Imperial-class Star Destroyer, creating an avenue for numerous other Mon Calamari cruisers to escape to the rebel-controlled Mako-Ta Space Docks.
Sometime following the Galactic Civil War, the racer Marcus Speedstar used hyperfuel to refuel his racer. He underestimated the hyperfuel's effect on his ship, leading his racer to spin out of control and crash into the stands, resulting in the deaths of his sister-in-law and niece.
Jarek Yeager, Speedstar's older brother, possessed a hyperfuel container in his private hangar. Jace Rucklin and his team had been trying to steal it for a long time, as it provides racers with a boost. They persuaded Kazuda Xiono to assist them, but the team was unaware that the fuel's drops could turn a ship into a giant bomb. While Xiono managed to rescue Rucklin, his racer exploded, and Rucklin vowed to take revenge on Xiono.
Following the Evacuation of D'Qar, Kazuda Xiono spearheaded the Warbird gang in a raid on the wreckage of the Fulminatrix to secure its coaxium for the Colossus.