Menkhaz the Unmortal, also known as "He Who is Bidden to Rule," was a Necron Overlord and the reigning Phaeron of the Khenisi Dynasty, a partially awakened Necron Dynasty that emerged upon the Imperial Mining World of Morsus in the Revenant Stars.
Like many of his kind, Menkhaz emerged quite insane from the millions of Terran years spent in hibernation known as the Great Sleep, but where other Overlords degenerated into blood-hungry Flayed Ones or embraced the nihilistic tendencies of the Necron Destroyers, Menkhaz's madness manifested itself in more subtle ways.
His inability to reign eventually led to his betrayal, sparking a civil war within the Khenisi Dynasty soon after the opening of the Great Rift. That conflict ended in Menkhaz's final death and the ultimate destruction of the entire dynasty at the hands of Mephiston, Chief Librarian of the Blood Angels Chapter.
Little is known of the Khenisi Dynasty's involvement in the War in Heaven and the part they played in the defeat of the Old Ones. As devout subjects of the Silent King, the Khenisi Dynasty was granted a string of Tomb Worlds hidden in what is now known as the Revenant Stars, the most important being Morsus. The Silent King entrusted Menkhaz the Unmortal with the safekeeping of a very rare and powerful weapon, an Orchestrion, a device most Imperial scholars and scientists believe originated in a different galaxy from the Milky Way. The technology could be used to link together entire Necron armies through unknown means.
When Menkhaz the Unmortal awoke from the Great Sleep, he was both more and far less then the Necrontyr he once was. While the millions of years spend in stasis had failed to do any harm on his new Necrodermis body, the millennia had gradually eroded his sense of reality, and while it still remains unclear which stellar event prompted the Great Awakening for the Khenisi Dynasty, it soon became obvious that the Phaeron was no longer fit to rule.
During the dynasty's long sleep, the Imperium of Man had colonised its principal Tomb World. Menkhaz's armies, led by his general, Nemesor Tekheron, waged war upon the Imperial armies of the Astra Militarum's Sabine Guard regiments who had intruded upon Khenisi territory that had colonised the dynasty's principal Tomb World during their long sleep, the Phaeron clearly had other preoccupations.
While Menkhaz agreed that Morsus was under attack, the ruler disagreed about the identity of their attacker. In his madness, Menkhaz was reliving the wars of his past, firmly convinced that Morsus was being besieged not by the armies of the Imperium, but that of the Aeldari. Consumed by his madness, the Phaeron ordered the armies of the Khenisi forth to ravage Morsus' surface in pointless bombardment runs or to occupy positions where there were no enemies to be fought.
To make matters worse, Menkhaz's orders depended upon the outcome of his daily tournaments of Crown, an ancient game once played by the Necrontyr. As none of his courtiers dared defeat their mentally unstable ruler, this led to a multitude of poor decisions. Although many amongst the Royal House disagreed with them, none dared not to defy the Phaeron's will, primarily because those who did were routinely executed by Menkhaz's Triarch Praetorians.
In an effort to emulate the court of the great Triarch, Menkhaz led his own triumvirate that ruled over the Khenisi Dynasty. Together with his consort, the bellicose Alakhra, and his brother, Menkhaz led his dynasty in an imaginary war against the Aeldari. The only counsel he listened to was that of his brother, who was a mummified Necrontyr corpse so old that his lower limbs had long since turned to dust.
Menkhaz the Unmortal dearly wished to leave his metal body behind him and ascend to the higher plane of existence that had once been promised to all of the undying Necrons after their biotransference by the Silent King. To achieve this goal, Menkhaz ordered his Crypteks to work on the Orchestrion and retro-engineer it into a powerful bomb that would annihilate Morsus and large parts of the Revenant Stars in an insane effort to ensure his dynasty's spiritual ascension.
As the Crypteks failed to deliver any meaningful results, Menkhaz executed them for failing, one after the other until he was eventually forced to petition other Necron dynasties for help. Overlord Osokhor agreed to send one of his most gifted Crypteks, the Heliomancer Xhartekh, to Menkhaz's aid. With unprecedented speed for the Khenisi bureaucracy, it took Xhartekh only five Terran years to reach Menkhaz's throne room. Time was of the essence, for during Xhartekh's long wait, the Great Rift had opened close to Morsus, threatening to consume the Tomb Word within the Warp.
Eager to work on a priceless artefact like the Orchestrion, Xhartek had little time to waste on formalities. Nevertheless he was soon caught up in the political games of Menkhaz's court. While the Phaeron still wished to use the Orchestrion as a weapon against his imagined foes, some amongst his court recognised the device's true potential and wished to use it accordingly. Xhartek's own goals aligned with those of these renegades, and so he agreed to restore the Orchestrion so that it could be used for its original purpose.
Much to his dismay, Xhartek discovered that one of the Crypteks loyal to Menkhaz had tampered with the Orchestrion, using the device's great power to restore the Khenisi Dynasty to its former glory and its undying Necron Warriors to a pristine condition. This would prove to be a fatal error, for in order to deploy its restorative powers, the Orchestrion needed to establish a permanent connection between itself and every Necron on Morsus. Little did the Cryptek know that this partial activation would draw unwanted attention upon Morsus.
Meanwhile, having encountered increasing difficulties in gazing into the future, Mephiston, the Chief Librarian of the Blood Angels Chapter, had been drawn to Morsus. In a daring raid, Mephiston and a small strike force of Blood Angels penetrated deep into the heart of the Khenisi Dynasty's subterranean capital tomb city of Nekheb-Sur. He eventually reached the lowest crypts where the Orchestrion was located. This was possible as a result of the civil war that had by then engulfed the Khenisi Dynasty. Recognising the folly of Menkhaz's plans, Nemesor Tekheron and the Phaeron's own consort had finally led their warriors in a rebellion against the forces loyal to Menkhaz.
Once at the heart of Nekheb-Sur, Mephiston used the link established by the Orchestrion to simultaneously reach every Necron on Morsus. He then used his own abilities to burn them out of existence with psychic fire. So passed from the galaxy Menkhaz the Unmortal and the Khenisi Dynasty.
- The Revenant Crusade (ca. 699.M41) - As the Necrons of the Khenisi Dynasty awoke from the Great Sleep, they clashed with the Astra Militarum regiments of the Sabine Guard tasked with the protection of Morsus. Loathe to abandon the rich promethium-mines located on the planet, the Imperium declared an Imperial Crusade to reclaim the Revenant Stars. The legions of Menkhaz the Unmortal battled the Imperial forces, but without the support of the Space Marines, the valiant men and women of the Astra Militarum could not prevail. After almost three Terran centuries of intermittent bloodshed, the newly resurrected Primarch and Lord Commander of the Imperium, Roboute Guilliman, declared an end to the Revenant Crusade, forfeiting those worlds to the Necrons. The Astra Militarum regiments thus freed up were rerouted as part of the Primarch's Indomitus Crusade.
- The Lord of Death Cometh (Unknown Date.M42) - In an attempt to explain the loss of his Second Sight, the Blood Angels' Chief Librarian Mephiston led a small strike force of Space Marines to Morsus. Accompanied by his loyal Equerry, Epistolary Rhacelus, and a single squad of Hellblasters, Mephiston landed on Morsus and penetrated deep within the Necron's necropolis of Nekheb-Sur. Allying himself with the survivors of Morsus' former population, both human and abhuman, Mephiston rekindled the Revenant Crusade and successfully defeated the Khenisi Dynasty.
- Mephiston - Revenant Crusade (Novel) by Darius Hinks, pp. 71-98, 189-278