The Core War was a war fought on Spherus Magna between the world's elemental tribes over possession of the Energized Protodermis that was found to be leaking to the surface from the planet's core. The Core War culminated in the planet-wide cataclysm known as the Shattering, in which the planet split into Aqua Magna, Bara Magna, and Bota Magna.
In the time before time, Energized Protodermis, an immensely powerful substance with the power to transform or destroy whatever it touched, appeared on the surface of Spherus Magna. The Element Lords of each tribe each desired to harness its power for themselves, so a war broke out between the tribes over the ownership of the substance. This conflict became known as the "Core War" because it was determined that the Energized Protodermis was working its way to the surface from the planet's core.
At least two tribes established minor outposts in the Bara Magna region of the planet as part of the Core War: the Jungle Tribe founded Tesara and the Fire Tribe founded Vulcanus. Most of the tribes established wells above Energized Protodermis springs and began draining as much of the substance as they could with no regard to what effects it could have on the planet itself.
Meanwhile, the Great Beings studied the properties of Energized Protodermis and realized that the tribes' uncontrolled mining of it had caused irreparable damage to Spherus Magna's infrastructure. In addition, the damage was predicted to be so great that it could only be a matter of time before the planet would split apart. The Great Beings then created a race of robots named Baterra to kill any armed combatants they encountered in a desperate attempt to put an end to the war, but soon realized that it was too late.
In 80 CMT, the Shattering occurred as the Great Beings had predicted and Spherus Magna split into three main planetoids: Aqua Magna, Bara Magna, and Bota Magna. Artificial atmospheric shells created by the Great Beings stabilized these chunks and kept most of their inhabitants alive, but the Great Beings themselves migrated to another planet. Despite their survival, the sheer destruction caused by the Shattering left few resources for the survivors that remained, so the Core War was brought to an end and a new societal system took its place.
In 150,081 CMT, Angonce recalled the measures the Great Beings had taken to stop the Core War - the creation of the Baterra - and proposed to the Council of the Great Beings that they should take similar action in regards to the Uterio War and design a new creation that would kill all Uterio War combatants that were not Great Beings, regardless of affiliation. TPK opposed this proposal because he feared that the phrase "Great Being" had become synonymous with "mass murderer" ever since the Core War, and he wished to restore their reputation.