Expulsion of Unicron

It was a brutal war, it was a bitter war, and most importantly, it was a visually spectacular war. Unforunately... I'm being told this would be very expensive to animate, so instead here's an image of the Thirteen charging into battle... with cool lighting!

Near the beginning of recorded Cybertronian history, the Expulsion of Unicron was the epic battle between the Chaos Bringer and Primus's chosen disciples, the Thirteen. More hellish and grueling than could be imagined, the Primes' battle concluded the ancient Primus-Unicron conflict with Unicron's defeat and banishment from Cybertron's region of the universe.

“	Before the beginning... There was Primus. And there was Unicron. One, the incarnation of creation—the other...of destruction. For eons, Primus and Unicron battled, the balance of power shifting between them more times than could be counted. Only by creating the Thirteen—the original Primes who preceded me—was Primus finally able to defeat Unicron and cast him out. Primus became one with the very core of our planet, creating life through the Well of All Sparks, while Unicron was never to be heard from again...until now.	”
—Optimus Prime, "One Shall Rise, Part 1"

Conceptual history

Primus, Unicron, and the Thirteen's shared story was slowly developed over the course of the 2000s.

The concept of the Expulsion of Unicron has arguably been around since the Marvel Comics issue "The Legacy of Unicron!", which introduced the first of many interpretations of the Primus/Unicron backstory. This original "Theomachy" between Primus and Unicron would be acknowledged and expanded on with 3H Productions's "Covenant". A story written by Simon Furman about the titular group, "Covenant" would introduce the idea of Primus creating unique beings who were created to protect the Grand Plan from Unicron. This basic idea would be recycled in Transformers: The Ultimate Guide, which established that Thirteen Primes fought Unicron at the beginning of history. During the 2000s, Aaron Archer would further develop the members of the Thirteen, creating sketches of the Thirteen, Unicron, and Primus.

Hasbro would finally provide the first glimpses of the Expulsion in the Aligned continuity's Transformers: Prime, which told the now standardized version of the Primus/Unicron/Thirteen mythology in "One Shall Rise, Part 1". Although Prime would show just a few still images of the Thirteen and Unicron, the prose novel Transformers: The Covenant of Primus would provide a much more in-depth version of the battle. The Covenant of Primus introduced the previously unknown members of the Thirteen, and explored how they developed a plan to defeat Unicron.

Since 2013, no other continuity has explored in-depth the Thirteen's battle against Unicron. The 2005 IDW continuity established uniquely non-mythological origins for Primus, the Thirteen, and Unicron, deliberately avoiding this concept. It did establish a conflict involving Primus and other gods of myth, but this conflict did not involve Unicron or the Thirteen. Subsequent franchises Cyberverse and EarthSpark would explore specific members of the Thirteen without mentioning Unicron, while One would depict the Thirteen as being at war with the Quintessons. The only continuities since The Covenant of Primus to hint at the Thirteen's battle with Unicron are Fun Publications's Another Light, which concluded the story of the multiversal singularity incarnations of the Thirteen, and Power of the Primes which featured Megatronus and Unicron.

Whether or not Hasbro will depict the Thirteen's battle against Unicron in future Transformers franchises remains to be seen.

Fiction

Aligned continuity family

Before the Expulsion

Long ago... before the time of Primes, Autobots, and Decepticons... a single being existed. As it roamed across a young galaxy and encountered life, it became confused and disturbed. Two voices began to develop within its mind. The first voice, Primus (meaning first and one), was reassuring and accepting. The second voice, Unicron (meaning unique and one), could not rest after seeing flaws and unanswered questions throughout the universe. The two voices began to oppose each other, causing the single being to split mentally and physically. Before they were fully separated physically, Primus and Unicron traveled with each other. Unicron would destroy what he encountered, and Primus would try to stop him or fix the harm he had done. Primus tried to reconcile with his twin, but Unicron refused to reunite as one uncertain being. Primus was filled with righteous rage, and the shared body between them fully split into two. The Covenant of Primus

Unicron became an incarnation of destruction as he continued to destroy all life, believing it would give him peace. Primus became an incarnation of creation, believing that it was his responsibility to stop Unicron. These two figures were ideologically opposed and evenly matched, an endless conflict that saw neither side achieving true victory. With prior attempts to defeat Unicron failing, Primus created the Thirteen. The Covenant of Primus One Shall Rise, Part 1

The Forge of Solus Prime was an important tool used to prepare for the Thirteen's battle.

Primus drifted into a slumber, preventing Unicron from sensing his location. Before falling asleep, Primus provided the Thirteen with a glimpse of his origins and various battles against Unicron. Alpha Trion, the Memory of the Primes, read the first entry of his Covenant of Primus, which allowed the Primes to understand that they were imbued with facets of Primus and Unicron's natures and abilities, which would allow for new strategies to combat the Chaos Bringer. Immediately following their creation, the Thirteen split into three groups:

• Warriors:
  • Prima
  • Vector Prime
  • Megatronus
  • Onyx Prime
  • Amalgamous Prime
• Strategists:
  • Alpha Trion
  • Quintus Prime
  • Liege Maximo
  • Micronus Prime

• Free Agents
  • Alchemist Prime
  • Solus Prime
  • Nexus Prime
  • The Thirteenth Prime.

The Thirteen quickly acknowledged that surprise was their greatest ally, and after studying Primus's battles with him, Solus created a virtual copy of Unicron to study and test various strategies against. It quickly became apparent that the Thirteen could not kill Unicron, although Quintus did suggest trying to defeat Unicron by "increasing his order", an idea that did not go far. They concluded that they would have to force Unicron into hibernation, just as Primus had.

Solus Prime crafted several artifacts to use against Unicron, such as the Requiem Blaster and Cyber Caliber. The Primes would also create the earliest version of Vector Sigma to run more realistic simulations of Unicron's attacks against them. After much frustration, Nexus and Alchemist devised a strategy that involved the Free Agents infiltrating Unicron's body and attacking his primary systems from within, causing a shutdown. Thirteen in particular would be essential to the plan: his unique spark would neutralize Unicron's anti-spark, allowing Vector Prime and Liege Maximo to trick Unicron's systems into entering a time loop of sorts. Armed with a plan, the Thirteen prepared to face their enemy... come what may. The Covenant of Primus

The Thirteen's Battle Against Unicron

Vector Prime opened a portal with the Blades of Time, allowing the Thirteen to see Unicron in person for the first time. Solus led the charge, the Free Agents right behind her. The Warriors and Saboteurs followed afterward, entering onto the cosmic battlefield. They were immediately hit with a wave of Dark Energon that emanated from Unicron's body, the Chaos Bringer's first line of defense. Prima fought Unicron with his Star Saber, striking Unicron's shoulder, while Onyx clawed and chewed on Unicron's back. Unicron grabbed Onyx, hurting him, as Megatronus and Thirteen pressed their attacks. Vector Prime began to enact the Thirteen's plan, creating micro portals that led to Unicron's interior, Solus once again being the first to enter. While trying to avoid Energon-seeker missiles, Alpha Trion accidentally hurt Vector Prime. Amalgamous tried to attack Unicron from behind in a sneak attack, as Prima defended an injured Onyx from further attack. Unicron taunted the Primes, searching for them, as Vector Prime pushed Liege Maximo and Alpha Trion into the micro portals.

The Anti-Spark of Unicron was the Thirteen's target.

Within Unicron's body, the Chaos Bringer's will nearly brought Alpha Trion and his siblings to their knees. Doubt and fear clouded Alpha Trion, but Thirteen's comforting words of "All are one" helped snap him out of Unicron's corruptive influence on his thoughts. Solus, Nexus, Alchemist, and Micronus had similar experiences, trying to mess with Unicron's systems as he assaulted the Primes with visions of death and corruption. Liege Maximo chose to attack Unicron with a unique weapon that pissed him off so much, he attacked his own body just to crush Maximo: words.

Back outside of Unicron's body, things were not going well. The remaining Primes outside of Unicron's body had been sent into seizures by one of Unicron's attacks. Megatronus accidentally fired the Requiem Blaster at Vector Prime, wounding him. Amalgamous and Thirteen would rush to Vector's side, providing medical attention. Unicron's attention turned towards the wounded Prima and Onyx, and it became clear that the time to enact the final part of the Thirteen's plan had arrived. Megatronus fired the Requiem Blaster once again, critically injuring Unicron's left arm. Amalgamous gave Vector the energy boost needed to micro-portal Thirteen into Unicron's body. Vector would communicate with Liege Maximo, giving instructions on how to set up Unicron's cycle counter so that the giant would be stuck within a time loop.

Just as Unicron was chewing on Prima, Thirteen arrived at Unicron's spark chamber. A few moments later, the Chaos Bringer completely shut down, with his body's last act being changing into a planetary alternate mode. The Covenant of Primus The Thirteen, against the odds, had defeated Unicron and cast him out. One Shall Rise, Part 1

Aftermath

With Unicron's defeat, the Thirteen Primes ruled over Cybertron during the Age of Primes. Although they had survived, many of the Primes had severe physical and mental wounds. Time would heal the physical wounds, but the darkness of Unicron began to feed off of their differences, which would slowly develop throughout the Age of Primes, resulting in the War of the Primes. The Covenant of Primus Primus would create new life through the Well of All Sparks, creating the race of Transformers. One Shall Rise, Part 1

Over time, matter gravitated toward Unicron's fallen form, eventually forming a planet which found an orbit around a distant star. One Shall Rise, Part 1 The Dark Energon that oozed from Unicron's body would be collected and stored in Trypticon Station. Exodus

During the Great War, Megatron achieved what Unicron did not by contaminating the core with Dark Energon, forcing the planet to shut down and reboot. Exodus Several stellar cycles later, the gravitational pull of a planetary alignment caused Dark Energon to erupt from the Earth, One Shall Fall and re-awakened Unicron from his long slumber. One Shall Rise, Part 1 The reincarnation of Thirteen, Optimus Prime, would lead his team of Autobots in battle against Unicron, eventually teaming up with Megatron to enter Earth's core and unleash the full power of the Matrix of Leadership. One Shall Rise, Part 3 Unicron would return again after Megatron's demise, reanimating the remains of Predacons into undead Terrorcons, who attempted to snuff out Primus on Cybertron. Optimus Prime would once again defeat Unicron, who would be trapped within the vessel that once held the AllSpark. Predacons Rising

Fun Publications

The "Multiversal" Thirteen waged their own (unseen) battles against Unicron.

Since time immemorial, the Thirteen, children of Primus, fought Unicron. Prima, leader of the Thirteen, wielded the mighty Star Saber in the Thirteen's conflicts with Unicron. Ask Vector Prime, 18/05/2015 Solus Prime forged the Terminus Blade for herself and her brethren to cross dimensions in their campaign against the primordial entity. Out of the One, Many

Prime Wars Trilogy cartoons

Long ago, Unicron threatened Cybertron, and Solus Prime created many tools to help defend against Unicron, including the Requiem Blaster. The Fight Begins Her lover, Megatronus, used the Blaster to vanquish Unicron. The Swamp

References

	Timeline of the Aligned continuity family
Theomachy (Expulsion of Unicron) Age of Primes (War of the Primes) Age of Evolution (Great Cataclysm) Age of Origins Age of Wrath Golden Age Age of Rust Great War (Great Exodus)