In 1984, Kenner started to brainstorm ideas on how to prolong the successful Star Wars toyline, as Star Wars: Episode VI - Return of the Jedi had premiered a year ago and by that time it was supposed to have been the final Star Wars film due George Lucas' lack of interest on making another film. Struggling to find ideas, the Kenner designers ultimately came up with the possibility of creating an entire new storyline picking up after the events of Return of the Jedi that could continue the adventures of Luke Skywalkers and the Rebel Alliance, devising the Star Wars: The Epic Continues toyline. Given that every Star Wars story needs an antagonist, Kenner created a original one, and Atha Prime was thus conceived. Coupled with other ideas, Kenner presented their ideas to Lucasfilm Ltd.
In Kenner's presentation for the character, Atha Prime was an egocentric genetics master and ruler of the "Dark Worlds" who was one of the architects who orchestrated the Clone Wars, a pan-galactic conflict mentioned as part of the original trilogy's backstory. Sometime after the war ended and the Galactic Empire rose to power, Prime was exiled from the Empire through unknown reasons and forced to reside in a remote fringe of the galaxy far, far away. However, following the death of Emperor Palpatine during the Battle of Endor, Prime is allowed to return from his exile and begin his intended bloody conquest of the galaxy with his clone army, which had been created with the power of his cloning technology. Prime has the starfighter Apex Invader as his personal headquarters, piloted by his droid Blue-Four, whereas Prime's flagship would be the double-decker Star Destroyer Annihilator (which has roughly the size of a city), which had a bridge complex that the Apex Invader could conect to.
With the Galactic Empire shattered after the events on Endor, Prime and his Clone Warriors start to secure control over the Imperial remnants and enslave worlds recently liberated by the Rebel Alliance to wipe out the Alliance and take over the galaxy, with his Clone Warriors replacing the Empire's Stormtroopers. However, to do so, Prime and his clone soldiers must fight against heroes like Luke Skywalker or Han Solo. Meanwhile, Grand Moff Tarkin (whose death the toyline intended to retcon) emerges from hiding after his supposed death during the Battle of Yavin and begins his own campaign to take over what remains of the Empire, opposing Prime.
The Kenner designers showed Lucasfilm their photos and sketches for Star Wars: The Epic Continues to get their approval. It's even suggested that Kenner may have wanted to produce a television show based on it like Star Wars: Droids or Star Wars: Ewoks. Unfortunately, while Lucasfilm was pleased for all the effort the company had gone through, they felt not ready to flesh out the Star Wars galaxy beyond the film installment, resulting in the toyline getting rejected. As a result, the Star Wars toyline came to an end tow years later in 1986 due lack of interest like Kenner had predicted. In regards to the franchise, it wasn't until 1991 that post-Return of the Jedi content started to be published with the release of Timothy Zahn's novel Heir to the Empire, which essentially reinvigorated interest on Star Wars and kickstarted the introduction of the Expanded Universe. Similarly, more film installments, including a prequel and sequel trilogies, would be released in the years to come, which precisely explored the Clone Wars and what happened after the Galactic Civil War.
- The design of Atha Prime was inspired by Nilo Rodis-Jamero's concept art for the members of the Emperor's Royal Guard during the pre-production of Star Wars: Episode VI - Return of the Jedi. However, Kenner made some adjustments on the design, which included changing the guard's axe-like weapon into a staff alongside slight alterations to the figure's headpiece. The Imperial Sentinels from Tom Veitch's comic book series Dark Empire were also inspired by this concept art.
- Atha Prime's role as the engineer of the Clone Wars was canonically filled by Emperor Palpatine and Count Dooku in Star Wars: Episode II - Attack of the Clones. Interestingly, back when Star Wars: The Epic Continues was being planned, it was commonly assumed by fans that the Clone Wars involved the clones being an invading force which attacked the galaxy, until the prequel trilogy revealed that the clones were the ones who defended the galaxy.
- While Star Wars: The Epic Continues was cancelled, the character of Atha Prime was subject by author Abel G. Peña to repeated attempts of canonization. Peña first wrote Prime into the backstory of the coup attempt in Star Wars: Empire: Betrayal, but such reference was cut from the final product. Peña then wrote him into an article of the Polyhedron magazine which consolidated Prime with the character Shadowspawn, who had been mentioned in the Dark Empire Sourcebook, but the magazine was cancelled alongside the article. In the end, Peña wrote a "genetics terrorist" in the 2007 Aliens of the Empire article, whom he intended to be Prime. When Matthew Stover's 2008 novel Luke Skywalker and the Shadows of Mindor featured Shadowspawn, some fans initially thought that Stover would canonize Peña's idea that Prime and Shadowspawn were the same character, but this was ultimately false and it was Cronal the character consolidated with Shadowspawn.