San'Shyuum, also known as Prophets by many individuals, are a near-extinct sapient species native to Janjur Qom. Prior to the Great Schism in 2552, the San'Shyuum served as the leadership caste of the Covenant. By that time, the San'Shyuum had exerted complete control over the Covenant's religious and political affairs.
Contemporary San'Shyuum civilization developed on a planet rich in artifacts left behind by the Forerunners, whom the Covenant would later revere as gods. Prophets derived their legitimacy as leaders as well as their colloquial names from this connection. The San'Shyuum of the Covenant originated from the Reformists, a radical faction that believed Forerunner technology should be deeply analyzed and fled Janjur Qom aboard the Forerunner Dreadnought after a lengthy civil war. According to the San'Shyuum, their home world was later allegedly destroyed in 648 BCE as the result of a natural stellar collapse. Because of this, they elected to make their home on the mobile planetoid station High Charity, powered by the Dreadnought.
The San'Shyuum waged a fierce and bloody war against the Sangheili between 938 and 852 BCE, halted only by their realization that the war would never come to an end. The two races united to learn their secrets, forming a mutually beneficial arrangement that would eventually become the Covenant, although they typically regarded themselves as above the Sangheili. The Sangheili became the protectors of the Prophets while the Prophets dedicated themselves to studying their "gods" and learning the secrets behind the "ascension" they left on.
Since the activation of the Halo Array and the subsequent reseeding, the San'Shyuum population has diminished. While their population at the time of the reintroduction was 500,000,000, there were only 23,831,463 living San'Shyuum by 2552. After the Flood invasion of High Charity, the majority of their species was consumed and it was estimated that less than a thousand members of the species still lived, assuming that the destruction of Janjur Qom did in fact occur.[3] However, a flotilla of starships capable of supporting thousands managed to evacuate surviving San'Shyuum from High Charity, with a secret destination set for the shield world of Cloister to hide from the vengeful Sangheili. The current status of this flotilla's voyage and whereabouts, are unknown to most in the known galaxy. Over the years, many of these ships were hunted down by the Shadow of Intent and their crews imprisoned until they stood trial. However, most were too proud to answer for their crimes and attempted to flee, only to be slaughtered.
In late 2559, the San'Shyuum Order of Restoration emerged from hiding under the leadership of High Lord Dovo Nesto -- the greatest and most powerful San'Shyuum to survive the destruction of both High Charity and the Covenant -- and set out to restore the Covenant empire. Following a failed attempt to take over the Domain through the Lithos, Nesto took control of the Covenant remnant once led by Sali 'Nyon to continue his efforts to restore the Covenant empire.
Regarded as a highly intelligent race, the San'Shyuum are a bipedal species, with very long, serpentine necks and limbs. When sitting in Gravity Thrones, they have an average height of 7 feet to 7 feet and 5 inches. They have an average weight of 179.4 pounds to 212.9 pounds. Contemporary San'Shyuum are lithe, gangly, and have frail skeletal structures which require slow and delicate movement: this is due to them being descendants of the ancient Reformist San'Shyuum who were used to lower gravity and bred from a small gene pool. The ancient Stoic San'Shyuumn who remained on their home world benefited from higher gravity and a larger gene pool which allowed them to be more muscular and physically fit. Members of the species generally have elongated heads, with prehensile, salamandrine lips. The slick skin of the San'Shyuum changes complexion with age; younger members of the species have light brown skin, with the complexion paling with age. Hair sparsely covered the body of a San'Shyuum, though many individuals had most, if not all, hair removed from their bodies. San'Shyuum have two large, amphibian-like eyes that vary in color among individuals, including shades of violet, brown, green, and blue. One San'Shyuum may have two distinct eye colors; having one dark green eye and one deep blue eye was once considered to be auspicious among San'Shyuum, but now denotes the individual as a member of a genetic line that was overbred. Young adult San'Shyuum have shorter necks, more prominent noses and chins and closer eyes than their elder counterparts, resulting in a marked resemblance to humans, enough for the two species to find one another attractive. San'Shyuum blood is colored red and differing blood types exist among the species. According to human designations, one of these types is referred to as E+.
Modern San'Shyuum, especially those that have spent considerable time in the low gravity of High Charity, tend to have some degree of difficulty moving in higher-gravity environments. Although younger San'Shyuum are significantly stronger and capable of walking upright, the majority of San'Shyuum in the Covenant are very elderly, and this combined with a life of physical inactivity leaves most of the Covenant's San'Shyuum withered and weak. As a result, most San'Shyuum wear some form of anti-gravity device. However, they are still capable of moving unaided, if only for a brief period of time. Prehistoric San'Shyuum were typically very lithe and muscular; both the Forerunners and humans considered the San'Shyuum to be very beautiful. After their surrender in the human-Forerunner wars, the San'Shyuum began to place their trust in the wisdom of often-paraplegic elders, though their warriors retained the musculature for which their species was renowned.
Millennia later, the San'Shyuum Reformists would come to adopt a similar sedentary lifestyle, although the Stoics who inhabited Janjur Qom remained noticeably more muscular, healthy, fit and could stand upright due to the planet's higher gravity and their genetic diversity. Some records suggest that the prehistoric San'Shyuum were genetically manipulated by the Forerunners at the end of the human-Forerunner wars, resulting in an unfortunate physical reduction of their species as punishment for their alliance with humanity.
San'Shyuum have distinct, often fur-covered, lobes of skin hanging underneath their chin similar to a beard, known as "wattles". Typically, only when an individual was deep into adulthood did a wattle weigh enough to slump down to their chin. As a result, the majority of younger San'Shyuum did not have prominent wattles, at least not under their chins. San'Shyuum also have fleshy, hanging appendages on either side of their head; despite their resemblance to ears, San'Shyuum ears are actually lobeless and located on the backs of their heads.
San'Shyuum are tridactyl-fingered—meaning that they have three digits on each hand, including a shorter thumb—with narrow, highly tactile hands. They are capable of, though typically unwilling, using handheld weaponry. Their prehensile, gnarled feet have three toes each, which are bent backward so that a San'Shyuum's weight is balanced on the knuckles of its feet. Their feet are often atrophied to a point of uselessness. This unconventional foot structure further complicates their movement when they are not being supported by anti-gravity systems.