They led the six ancient guilds with seven guildmasters at the head of each one, occupying a space between gods and mortals in the eyes of their servants. Though they were not gods themselves, their unbelievable power still captures the devotion of mummies in the modern day.
The Iremite word "Shan'iatu" had the connotation of a steward and representative, likely referring to the representation of the Shan'iatu to the gods before humans. One honorific was "Presence of the Judges". From it, the Egyptian word "shanitu", roughly “assistant who is a judge” would be derived after the fall of the Nameless Empire. 
The exact origin of the Shan'iatu is difficult to pin down. In the texts of one of the Deceived, they are referred to as creations of the Judges (referred to as the Judges of Life) that were direct emanations of the primordial Nomenclature. The first Shan'iatu were servants of Azar and were instructed to keep Ammut's influence in the world contained. It should be noted that the Shan'iatu are most decidedly not human. Their essence is described as "magic given voice and shape", and one described himself as "a son of the stars [...], a man born of fire, as you [the early humans] were born of ever-changing earth", they were natural shapeshifters and differed from humans in the aspect that they were not creatures of Sekhem, but of the Temakh, and as a result, they lacked a soul. Indeed, the Shan'iatu were first fashioned after human form, designed to guide them to accept the rule of the Judges and safeguard them from Ammut.
The tome of the Heretic records Iremite doctrine called the "Hymns of the Creation of the Temakh" that tells that the Shan'iatu are emanations of the Judges of Duat, created in response to the rebellious nature of the gods. Since the Judges can only assign people that have sinned to Ammut, they instructed the Shan'iatu to teach the early humans about the Law, but also to teach them sin so that they might be consigned to the Devourer.
Before Irem, the Shan'iatu learned the secrets of the world, where they first met humans, which were called Remet, "the Weeping Ones", because they suffered death. When they first observed death and met the Nameless God Anpu at the threshold to the afterlife, where they were told that the souls of mankind traveled through life, into the presence of the Judges and to the life after life, A'aru. As children of the Temakh, the Shan'iatu could not partake of this and their duty was solely to prepare the humans for this until the last of them had died and been judged.
In the meantime, the influence of Ammut had grown in the world. The first Amkhata stalked the Remet and the Shan'iatu were called to protect them. One of them (who is only revealed to have been one of the Deceived) lost its entire tribe except for a young woman named Aset and was wounded by Ammut's creatures. He took her with him and taught her the language of the Nomenclature. When it tried to rest himself from it wounds, his spirit ventured to Neter-Khertet and was found by Ammut. The Great Beast taunted it, describing it as a slave to the Judges and the Remet and seduced them to replace Anpu and make Azar the warden of Duat.
The death of AzarEdit
The Shan'iatu, along with others that had been wounded similarily, then came before Azar and hacked him into 43 pieces with a claw forged out of meteoric iron. Then, Aset was forced to eat 42 of these pieces, and after 43 nights, a new god was formed inside her. Then, they killed Aset, allowing Azar to descend to Duat and claim its Sekhem from Anpu, to be allowed as the Judges of Death. After Aset's death, a new star shone at the sky, called Sopdet and later referred to as Sothis.
However, Azar did not call his former servants to Duat and Anpu was not destroyed, but reassigned to Neter-khertet, to keep watch over the boundaries between life and death. The Shan'iatu came together and discussed what had to be done to earn their king's favor. They remembered the duty they had been given and decided to gather the Remet under their leadership, but keep the laws of the Judges of Life from them. Instead, they would be tutored in the law of the Judges of Death that they sought to become.
The Heretic confirms this course of events, but according to him, Sothis already existed before, having been a creation of the god Sutek. Here, the Shan'iatu claim to have discovered the legacy of Sutek that allowed mortals to leave this world and ascend to A'aru, the Will. Because of this, Azar submits to them.
The Necromancer SenateEdit
The Shan'iatu came to predynastic Egypt when it was not yet urbanized or practicing agriculture. They brought the people together under their harsh rule and created the kingdom that would lead to Egypt's Old Kingdom, the Nameless Empire of Irem. Ruling over the Remet with an iron fist, they installed a puppet ruler named Pharaoh who was to resemble Azar in ceremonies. In time, the Shan'iatu became decadent, aping the pleasures of the Remet, and slowly losing their primordial powers. They proved, however, to be powerful enough to put any rebellions against their rule down. Concerned by the loss of their power, the Shan'iatu debated and eventually agreed to seek out Ammut a second time, to learn how to bring the Nameless Empire into Duat and create immortal servants. In the mean-time, they studied Sekhem by locking souls into bodies, which proved vaulable when Irem met Ubar, a city ruled by the Ki-En-Gir, wizards without connection to the Nomenclature. When they had crushed Ubar down and tortured its wizards to death, Ammut sent a messenger with further instructions on how to preserve their Empire.
According to the Heretic, the weakness of the Shan'iatu sprang from the fact that they tried to learn the art of Will, the choice between A'aru and Ammut, they were supposed to teach the remet themselves. Since their Temakh possessed no Pillars, they could not correct or learn from their own mistakes, becoming fixed and weakened beings, unable to transcend their own transgressions. Unable to question beyond the purpose their Judge gave them, they conspired to take their masters place. 
The Rite and the BetrayalEdit
At Ammut's instruction, the Shan'iatu constructed a rite that would allow Sekhem to pass into Duat and yet return. By doing so, they would ensure that the Remet would follow Azar's and the Judge's designs, so they would have fulfilled their purpose and could take the place as the Judges of Death. These servants became the Arisen.
Seven Shan'iatu, those of the Akhem-Urtu guild, voiced doubt on the Rite and how smart it was to trust Ammut. They sought answers and found them from Anpu, who reminded them of their ancient betrayal against Azar, which had shaped the world by creating a new True Name for the concept of "king". The seven were the masters of the Nomenclature, the magic of True Names, and they sought to make themselves Judges of Life and Death by modifying the Rite to enthrone themselves above the others. Unbeknownst to them, the other Shan'iatu had learned of the treachery planned by the Akhem-Urtu and answered by manipulating the Rite to split the essence of these seven into their servants. Each of these Shan'iatu fragmented into seven shards that possessed those Arisen that would have served them.
What became of the others is not known. Memory clouds it and those who were deceived have no clear recollection. It is known, however, that they used the slaves who would later become the Shuankshen as a sacrifice to Ammut to pay for such a mighty working and anointed the pillars of their capital with blood to bring it down to Duat.
The Heretic speaks of the fate of those Shan'iatu that succeeded. They managed to enter Duat, since they had Named Azar their king and were protected from the hazards and trials of the realm. The only way they managed to pass through to the center of Duat, however, was through the sacrifice of mortals and the use of the Rite of Return. While the future Arisen could leave Duat by stating his Decree, the Shan'iatu lacked any Pillars of their own and thus could neither leave this realm to reach A'aru nor be judged by their masters and sacrificed to Ammut. Instead, they were confined to houses within the City of Black Spines, doomed to feast on ashes and vinegar by the Judges of Duat whom they sought to supplant. Their only connection to life is the Arisen bound to the same Judge as they themselves, so they seek to manipulate him to steal Sekhem found in the living world to transform their feast into wine and roasted flesh, eventually hoping to reach A'aru through scavenging the world of the living.  The Arisen know nothing of this, believing instead to serve the true Judge, rather than the Shan'iatu that is now trapped in Duat and desperate to gain power to escape his imprisonment.
The Shan'iatu that were betrayed believe that the Judges the Arisen believe to serve are their former compatriots, having achieved their goal and claimed dominion over Duat. This grudge drives them against their former brethren.
- ,p 18-28