Sanghelios

Sanghelios is a dimension that can be reached using the Forerunner Transport Artifact.

Physical Aspects
Sanghelios' terrain is mostly red desert, with a few jungles and large oceans. Various statues of Sangheili warriors can spawn under large cliffs. Within 'Vadam Keep, the player can enter 'Vadam palace or the council chamber. Within the Csurdon Sea, the player will encounter the great city of Sunaion. Sanghelios is also littered with various cities, Forerunner structures and artifacts, and individual Sangheili palaces and keeps. Mobs from the Swords of Sanghelios will spawn within the cities and keeps, while mobs from Jul 'Mdama's Covenant will spawn in Sunaion. Civil wars are frequent on Sanghelios.

Info
Sanghelios is the homeworld of the Sangheili, the co-founders of the Covenant. The Sangheili were one of many species that were re-seeded after the firing of the Halos. Like the Stoic San'Shyuum, the Sangheili believed Forerunner artifacts holy and deemed it heresy to tamper with them. However, some Sangheili scientists went behind the government's backs, and developed advanced technology in secret. The Sangheili created ships with slipspace technology, and colonized dozens of worlds within the next several thousand years.

Following decades of war with the San'Shyuum, both races signed the Writ of Union, the basis of the Covenant. Sanghelios was originally planned to be the Covenant capital world, but with the construction of High Charity underway, High Charity was made capital. The Sangheili would continue colonizing worlds and grafting new species into the Covenant for the next few thousand years.

After the Great Schism, Sanghelios and all Sangheili colonies broke away from the Covenant, and thus aiding humanity. However, after the war, some Sangheili did not want to follow the Arbiter in his alliance with humanity. As a result, many Sangheili broke away from the Arbiter and formed their own factions, many of which were reminiscent of the old Covenant. The planet itself served as a vantage point for Jul 'Mdama's Covenant, until Jul 'Mdama was killed by Fireteam Osiris, by which time the remnants of the Covenant were at Sunaion.