Transformers Cybertron
Cybertron is the home planet of the Transformers and (usually) the body of their creator, Primus. Cybertron is (almost always) a shining metal, technological world; a planet of towering future cities without end and vast metallic plains, spiraling metal mountains and bottomless neon-lit chasms. Battling over control of Cybertron and its resources is frequently the motivation for, or origin of, the Transformers' epic wars. Beyond these facts much about Cybertron can differ between continuities, see individual entries below.
History
Cybertron was a living mechanical planet and the homeworld of the Transformers. At its core existed the AllSpark, a massive spark from which all other sparks originated; these sparks would travel up through the Well of All Sparks to the planetary surface to be forged into new Transformer life. Conventional mythology holds that the Thirteen were the first Cybertronians; it was Solus Prime who created the Firstforged, a second generation of Transformers who laid the groundwork for a global civilization. End of Time The Reversionists believed that Cybertron was the transformed body of Primus, who had surrendered his physical form to create a home for his children. When a Cybertronian grew tired of living, they could chose to go "immersant", a voluntary ego-death where their bodies and minds gradually merged with the planetary strata until their spark permanently left their body and rejoined the Allspark. Escape Part Two Many Titans chose to go immersant outside Iacon; their jumbled remains eventually became the Cybertronian Mountains.
During the Age of the Firstforged, early heroes like Halonix Maximus tamed the wilderness, battled bestial Transformers like Preditron, Tremors and raised towering works of art like the settlement that would eventually become Crystal City. The Cybertronians established a planetary Senate in Tarn, Prime led by a Prime, who served as the assembly's "First Senator"; the Forge Pyramid in Iacon became the nexus of new Transformer life, where the sparks that arose from the Well of All Sparks were forged into new Transformers. Early in Cybertron's history, a a group of Cybertronians used the Enigma of Combination to become "The Abomination", a monstrous, fuel-guzzling combiner which ravaged the planet until a group of Transformers successfully felled the creature in Iacon. At some point, the Senate was later relocated to Iacon.
During Cybertron's ancient history, the Titan Chela saved the planet from a rogue comet. During the Age of Expansion, the people of Cybertron colonized many new worlds and vanquished rival galactic powers with the assistance of the mighty Titans. The Change In Your Nature Part Five During this prosperous age, Cybertron was invaded by rust worms, rust-secreting metallivores who threatened to consume the entire planet. Efforts to neutralize the creatures failed; in the end, Cybertron itself sealed them away within an impenetrable basin, which became the Sea of Rust. Sea of Rust I The Age of Expansion came to an end when Exarchon was corrupted by forces unknown while on an extraplanetary voyage; he returned as a living virus capable of snuffing out the sparks of other Cybertronians and incorporating their bodies into his tripartite collective. War's End Part One The subsequent War of the Threefold Spark saw the mass conscription of many Cybertronians. The final battle of the war was fought outside Iacon; while Exarchon was seemingly vanquished, the cost of victory proved high, and cities across the planet were left in ruins.
Realizing that their reckless expansionism had brought Exarchon down on their heads, then-Autobot leader Nominus Prime passed the Nominus Edict, which effectively curtailed any future colonization endeavours, mandated laws regarding energon rationing and storage, and limited the forging of any new Transformers. The Change In Your Nature Part Three Nominus made the decision to end the creation of new Titans; future Titansparks were placed in storage in a hidden room beneath the Forge Pyramid. War World: Titans The remaining Titans were repurposed into an orbital defense fleet that would protect the planet from spaceborne threats. The World In Your Eyes Part One Nominus Prime's term saw the rebuilding of Iacon Constructicons Rising, Part 1 the construction of the Winged Moon, a massive energon-harvesting station that would provide Cybertron with limitless energon, and the Tether that connected it to Cybertron. Orion Pax: Free Fall While some Transformers looked back on the past with regret, noting that their expansion had caused other races to fear their destructive nature, The Change In Your Nature Part Five other Cybertronians like Termagax mourned a lost age of prosperity and potential that'd been cut short and felt that the Nominus Edict had overstayed its welcome.
Trivia
Lots.