Sangheili

The sangheili are a sapient saurian species native to the planet Sanghelios.
== Biology and appearance ==
Sangheili are muscular and very tall, usually standing between 2.25 and 2.62 meters (7.38 and 8.6 feet). Their eyes are positioned on the sides of their head giving them monocular vision. Their jaws are quadruple-hinged, with an upper jaw and four lower mandibles arranged in two tiers. Due to their predatory nature, the species' sense of smell is highly developed.
Their hands are tetradactyl, each having two fingers in the middle and an opposing thumb on either side. Contrary to what their anatomy might suggest, sangheili can release a loud, sharp and piercing whistle by placing their thumbs on the same hand into their mouths and blowing through the narrow gap. Their legs are digitigrade, with short upper and lower legs, and elongated tarsals, using the distal and intermediate phalanges to support their weight when walking. This arrangement possibly allows them to run very quickly and jump large distances, compared to ordinary humans and other Covenant races. Their superior agility may also be attributed to their homeworld's higher gravity; the additional strength required to move normally in a high-gravity environment would likely cause them to be more powerful in lower gravity situations (though, curiously, their tall, large, and lean figure would be extremely disadvantageous and impractical on a high-gravity planet—an arrangement possibly allowed by other major factors in their biology and life cycles). They also appear to have a double set of pectoral muscles, which contributes to their incredible strength. On the other hand, their digitigrade stance makes it difficult for them to climb vertical constructs such as ladders.
== History ==
=== The Ark and reseeding ===
The sangheili evolved in tropical wetlands of their homeworld, Sanghelios. Sanghelios had at one point been visited by or had been in contact with the Forerunners. During the War for the Dawn, the Librarian visited the planet to retrieve specimens of the sangheili for preservation aboard Installation 00. After the firing of the Halo Array, they were returned to their home planet to begin rebuilding their culture.
=== Development of civilization ===
After being returned to their homeworld, the sangheili discovered artifacts left by the Forerunners on their planet. The Sangheili revered the objects these "gods" had left, and considered tampering with them a heresy beyond any other. However, some sangheili scientists defied their species' dogma and studied Forerunner artifacts in secret; they would later become instrumental in helping the Sangheili reverse-engineer weapons against the san'shyuum. Several hundred years prior to the formation of the Covenant, the Sangheili had developed slipspace technology and created dozens of independent colonies, though their homeworld of Sanghelios remained central to governance and culture. The planet of Creck, discovered before the Sangheili's contact with the san'shyuum, was the seventy-sixth designated world explored by sangheili.
=== The Covenant ===
The sangheili eventually encountered the Reformist san'shyuum, a race who also worshiped the Forerunners as gods, but had utilized Forerunner technology for their own needs, believing the technology had been left behind by the gods as gifts for their children. This sparked a war between the two races over how to treat the relics. Even though the sangheili were much more physically imposing and numerous, they suffered extreme casualties under the sheer power of the san'shyuum's Dreadnought, a surviving keyship, and, ultimately, even the most devout had to admit their survival depended on the reconstitution of their own Forerunner technology. This led both sides to an agreement that ended with the decommissioning of the Forerunner Dreadnought and a shaky alliance that eventually expanded into the Covenant.
=== The Great Schism ===
Eventually, a political shift caused by the High Prophet of Truth and Tartarus, the Supreme Chieftain of the jiralhanae, started a slippery slope that ended in the dissolution of the Covenant between the sangheili and the san'shyuum. Originally, the jiralhanae were viewed as savagely aggressive and extremely goal-oriented, which the sangheili viewed as a serious threat should they ever begin to desire political power. This fear became reality when the Honor Guards of the Prophets, originally an all-sangheili class, were replaced by the jiralhanae. This was directly caused by the assassination of the High Prophet of Regret, despite Regret's protection from his personal squad of sangheili Honor Guardsmen. Soon the jiralhanae found themselves in new positions of power, effectively becoming replacements for the sangheili. During the concurrent Battle of Installation 05 and the Fall of High Charity, the jiralhanae had begun to massacre the sangheili under Truth's orders. Additionally, Arbiter Thel 'Vadam and Special Operations Commander Rtas 'Vadum discovered the truth of the Halo rings from the Monitor 343 Guilty Spark. From this, they learned that the Prophets' promises of the Great Journey were false causing further turmoil.
These events led the entire sangheili species to secede from the Covenant, unified to bring down the empire that had betrayed them. They were aided by a few of the member species within the Covenant, such as many unggoy and most lekgolo, although many sided with the High Prophets despite the sangheili's efforts. The secession included a movement to destroy the treacherous jiralhanae and High Prophets, and the destruction of the Flood at all costs.
=== Fall of the Covenant ===
Following the destruction of the Covenant, sangheili society plunged into crisis. Already lacking centralized governance and splintered to independent city-states spread across several dozen major colonies, they fractured into multiple infighting factions with varying ideas on how to run their society, despite their ongoing war with the jiralhanae. This was largely due to the fact they had become reliant of the Prophets during the millennia of the Covenant's existence. As they regained their independence, they were forced to re-learn how to manage their society on their own, without the direction of the Prophets.
During this time, Arbiter Thel 'Vadam managed to gather a sizable alliance of keeps under the banner of the Swords of Sanghelios, which became the preeminent governmental entity among the sangheili. Many other factions, such as the Servants of the Abiding Truth, opposed Thel 'Vadam and his allies, specifically their rejection of the notion of the Forerunners being gods. This eventually led to the Sangheili civil wars known as the Blooding Years.
== Known individuals ==
Ussa 'Xellus - Leader of the Ussans, an early rebellion against the Covenant.
Quillo 'Crecka - An Ussan, close confidant of Ussa 'Xellus.
Thel 'Vadam - Former Supreme Commander of the Fleet of Particular Justice, current Arbiter/Supreme Consulate of the Unified Republic of Sanghelios.
Rtas 'Vadum - Former Special Operations Commander, current Supreme Commander of the Sangheili Republic Starfleet.
Ikusaa 'Veran - Founder and martyr of the Ikusaan separatists.