Large Magellanic Cloud

The Large Magellanic Cloud, also called the Greater Magellanic Cloud and known as Path Kethona by the Forerunners, is one of the two Magellanic Clouds, located 160,000 light years from the Milky Way.

Forerunner-Precursor war
A local dwarf galaxy orbiting the Milky Way, Path Kethona was once the site of Precursor activity. One local system was home to a network of star roads unlike anything seen in the parent galaxy. After the Forerunners rebelled against the Precursors, around ten million years BCE, and began a genocidal campaign to root out their creators, the Precursors eventually retreated to Path Kethona. However, the Forerunners followed with an enormous fleet of warships, constructing a series of probability mirrors to reconcile the massive causal breaches caused by the transit. All but a few Precursors were exterminated; a small number survived by entering suspended animation or reducing themselves to molecular powder programmed to reconstitute their forms at a later time. Ships bearing the powder were sent on their way toward the Milky Way, some eventually crashing on worlds in the galactic margins. Millions of years later, the Precursor molecules—corrupted over the eons—would spawn a virulent parasitic lifeform: the Flood.

During the war, some Forerunners serving aboard the fleets sent to Path Kethona began to object to the complete genocide of the Precursors as a crime against the Mantle. Many of these dissidents were summarily executed, while some were exiled on a barren world named Sedaaro within a nebular region known as the Spider. An artificial ecosystem was constructed entirely from Forerunner genetics to sustain the Forerunners on the planet, who would come to adopt a primitive lifestyle and undergo divergent evolution from the mainline Forerunners, resulting in several physiological differences between them. Ironically, the marooned Forerunners would outlive their former compatriots who finished the genocide, the latter never returning to the ecumene out of immense guilt over their actions.

During this time, two Precursors had found shelter and were found by the Forerunners who hid them and tried to heal them. However, the Precursors were beyond the Forerunners' ability to save and although the Precursors possessed the ability to heal themselves, they chose to let nature take its course. After dying, the two Precursors became samples that were studied and encoded, seeds that germinated for a million years. Sprouts that climbed to the surface took even longer and bloomed only in the last million years. Unlike the Primordial, these were Precursors that celebrated joy instead of relishing in suffering and as a result, the blooms are not left corrupted with violence and misery but instead are clean, beautiful and bright.

Forerunner-Flood war
Meanwhile, the truth about the passing of the Precursors faded into legend and was eventually forgotten over the eons. According to the ancient myths of the latter-day Forerunner civilization, prehistoric Forerunners had conducted a great scientific expedition to Path Kethona more than ten million years earlier, a distorted version of the final phase of the genocide of the Precursors. In addition, prevailing theories held that the satellite galaxy was the point of origin of the Flood. Several millennia after the Flood's first emergence, around 98,395 BCE, the Librarian organized and led an expedition to Path Kethona with the intent of examining the origins of the Flood as well as the veracity of the legendary Forerunner expedition. Aboard the ship Audacity, the Librarian and her crew of seven traveled to Path Kethona. Initial scans found the galaxy seemingly devoid of technological civilizations—or any life at all. In one system, however, the crew of Audacity discovered an impressive network of Precursor artifacts—as well as a fleet of ancient Forerunner warships and the probability mirrors used to reconcile their arrival millions of years earlier.

Further scans revealed a single planet orbiting an orange star with a possibility of supporting life. Traveling to Sedaaro, the Librarian and her crew discovered the primitive Forerunners and the planet's peculiar ecosystem. The Librarian was taken by a local female to a moss-like growth which had adapted to record the locals' history. It was through this repository of knowledge that the Librarian learned the origin of the locals, as well as the true nature of the prehistoric Forerunner expedition to Path Kethona: while ancient Forerunners had indeed traveled to Path Kethona, the journey had not been for the purposes of exploration, but to eradicate the last of their creators. Deeply distraught, the Librarian and her crew subsequently returned to the galaxy; she did not reveal what she had learned to anyone, until her testimony to Catalog over 900 years later.

Driven by her own geas from the Precursors to fix the path and set right what the Forerunners did wrong, the Librarian located the specimens left behind by the two Precursors that had chosen to die. Returning home with the specimens, the Librarian kept her discovery out of her report to the Ecumene Council and enlisted the help of the crew of the Audacity to transform a small shield world in its construction phase, Bastion and make it what it needed to be to nurture this eventual new species. The Librarian had the starship Eden built to carry the Precursor seeds and blooms to a world outside of the Milky Way galaxy that is ideal for planting and growth and where they can't be reached by the Flood. There, in some distant future, life on the planet will emerge and grow sentient, following the complete genetic code of the Precursors and rebirthing the race. However, they will be utterly free of genetic memory and will be able to build a new civilization with a clean slate.

All life and Precursor architecture in Path Kethona was wiped out when Master Builder Faber fired Omega Halo's directed pulse toward the satellite galaxy during the Battle of the greater Ark in the last days of the Forerunner-Flood war in 97,445 BCE.

List of appearances

 * Halo: Silentium
 * Halo: Point of Light