Sanghelios global war

A global war on the Sangheili homeworld of Sanghelios erupted in late 2558. Fighting would involve the Swords of Sanghelios, Jul 'Mdama's Covenant, minor forces of the United Nations Space Command (UNSC), and finally the newly formed Created.

Standoff
At some point, Jul 'Mdama's Covenant would gain control of Sunaion and began to plan for a strike on Vadam. The Swords of Sanghelios would be made aware of this and would establish a forward operating base in the ruins of Nuusra. They would hope to strike the Covenant at Sunaion.

Leading into the conflict, Sanghelios was in a tense state.

Preparations
Following the setback at the Absolute Record, Jul Mdama and his Covenant pivoted to trying to take control of Sanghelios. To this end, Covenant forces would take control of the Argent Moon and scour it in hopes of finding any materiel to help with this goal.

Ignition of conflict
Around October 17, 2558, Jul 'Mdama's forces besieged Sanghelios. As their forces attacked, other assets on the planet rose up and Sanghelios burst into a worldwide conflict. Heavy fighting took place in most of the planet's city-states. Despite the conflicts on the planet previous to this point, this was the first time that fighting on Sanghelios was characterized as a global war.

Although the Arbiter did not formally request support from the UNSC, personnel on the were given a warning order that intervention to support the Swords of Sanghelios might be required.

A member of the House of Vadam, Murok 'Vadam, would divulge the location of where the Arbiter was stationed to the Covenant in exchange for power and prestige.

Fighting at Nuusra
"With Arbiter's victories and the death of Jul 'Mdama, the Covenant grow desperate. They have began an assault on 'Vadam lands, targeting Arbiter specifically."

- Mahkee 'Chava to Fireteam Osiris.

On the morning of October 27, 2558, the Covenant made a last-ditch attempt to kill the Arbiter at Nuusra. Partway through the battle, the Spartans of Fireteam Osiris would assist Swords forces in repelling the Covenant and extracting the Arbiter Thel 'Vadam.

After discussions took place between human forces and the Swords, Fireteam Osiris would move to a Forerunner installation to retrieve a Constructor.

With it, the humans modified it to activate the Guardian beneath the sea city of Sunaion. Sunaion was also at this point, the Covenant's last stronghold. Together, the humans and the Swords of Sanghelios left Nuusra to attack.



Last stand
"The Covenant soldiers will hear the Guardian wake from its slumber, they will look up over the bodies of their brothers, through the smoke of their burning city, they will look to the horizon as their holy idol rises from the sea and forsakes them. And that is when the Covenant dies."

- Thel 'Vadam to a few of his officers.

The Swords of Sanghelios moved into Sunaion deploying Thel himself and Fireteam Osiris. They would split up with Osiris moving to take out anti-aircraft weapons. At least one ship in the air above the battle fell into the Csurdon Sea below. Osiris eventually went into the under city fighting Covenant forces there. The Guardian buried below began to rise, and with it Created forces joined the fray.

List of appearances

 * Halo 5: Guardians
 * Halo Mythos: A Guide to the Story of Halo
 * Halo: Legacy of Onyx
 * Halo: Bad Blood
 * Halo: Official Spartan Field Manual