Rehati

Legion Badge of the Thousand Sons after the Horus Heresy

The Rehati served as the Thousand Sons Legion's inner coven of advisors and was comprised of the most trusted confidants to the Primarch Magnus the Red throughout the Great Crusade until the start of the Horus Heresy in the early 31st Millennium. 

The Rehati were drawn from the ranks of the elite captains of the XV Legion's Fellowships to address whatever issues were currently concerning the Legion. Its members were ever-changing, and inclusion within the Rehati was dependent on many things, not least of which was an Astartes' standing within the Legion.

The original five pre-Heresy Cults of the Thousand Sons vied for prominence and a place in the Primarch's inner circle, knowing that to bask in his radiance would only enhance their psychic powers.

As the power of the Empyrean waxed and waned, so too did the mystical abilities of the cults. The Rehati served a similar position for the Thousand Sons that was comparable to the Mournival of the Sons of Horus Legion.

Following the devastation of their homeworld during the Fall of Prospero and the Legion's mystical migration to the Eye of Terror, the Rehati became made up of a coven of nine Exalted Sorcerers and Daemon Princes favoured by Tzeentch that hold the rank of Magister Templi.

Each Magister Templi of the Rehati led one of the nine Post-Heresy Cults of the Thousand Sons. Each Cult in turn is divided into nine Sects commanded by lesser Sorcerers and Daemon Princes. These in turn are further divided into thrallbands, which make up the basic fighting units of the Thousand Sons Legion in the 41st Millennium.

Notable Rehati Members

• Ahzek Ahriman - Ahriman is the former Chief Librarian of the Thousand Sons, Captain of its 1st Fellowship and the Magister Templi of its Corvidae Cult. He was banished from the Legion after casting the Rubric of Ahriman using the knowledge of the Book of Magnus, which halted his Legion's corrupting mutations which plagued it after their fall to Chaos, but resulted in the creation of the Rubric Marines. During his banishment, Ahriman has continuously sought out knowledge across the galaxy to bring him closer to an understanding of Tzeentch and Chaos itself and led a warband of similarly-exiled Chaos Sorcerers and Chaos Space Marines known as the Prodigal Sons. His actions have recently healed the breach between him and Magnus the Red that was opened by his casting of the Rubric of Ahriman.
• Phosis T'Kar - T'Kar was the Captain of the Thousand Sons' 2nd Fellowship during the latter days of the Great Crusade and the beginning of the Horus Heresy in the late 30th and early 31st Millennia. As one of the most powerful telekines of the XV Legion, he served as the Magister Templi of its Raptora Cult. Phosis T'Kar met his ultimate fate during the Burning of Prospero, when the Space Wolves Legion, accompanied by elements of the Legio Custodes and the Sisters of Silence, were sanctioned by the Emperor of Mankind to punish the Thousand Sons Primarch Magnus the Red for the blatant violations of His Decree Absolute rendered during the Council of Nikaea forbidding the use of psychic powers and the pursuit of sorcery. During the height of the battle, Phosis T'Kar was physically corrupted by the "flesh-change" and surrendered to death at the hands of the Legio Custodes commander Constantin Valdor.
• Hathor Maat - Hathar Maat was the Captain of the 3rd Fellowship of the Thousand Sons Space Marine Legion during the latter days of the Great Crusade and the beginning of the Horus Heresy in the late 30th and early 31st Millennia. He also served as the Magister Templi of the XV Legion's Pavoni Cult. Hathor Maat was present during the Burning of Prospero, when the Space Wolves Legion, accompanied by elements of the Legio Custodes and Sisters of Silence, were sanctioned by the Emperor of Mankind to punish the Thousand Sons Primarch Magnus the Red for his blatant violations of the Imperial Decree Absolute rendered during the Council of Nikaea forbidding the use of psychic powers and the pursuit of sorcery. He was one of the few survivors of the massacre who escaped when their mortally wounded Primarch Magnus the Red teleported them to the Planet of the Sorcerers within the Eye of Terror. Maat was one of the Thousand Sons captains who Ahzek Ahriman knew would be easy to sway to his Cabal to stop the flesh change. Maat later accompanied Ahriman on his quest to track down the Shards of Magnus. However, he began to suffer from the flesh change. Striking a bargain with the Greater Daemon "Aforgomon" and the Emperor's Champion Lucius who were accompanying Ahriman's cabal in their quest, Hathor Maat learned to hold off the flesh change by sacrificing captive humans. Aforgomon further manipulated Hathor Maat into altering a single line of the Book of Magnus. However when Ahriman's cabal finally came to the shards of Magnus at Nikaea, the change finally over came Maat. Paying the price owed to Aforgomon, Ahriman sacrificed Maat to allow the daemon to possess the Thousand Son's body and manifest as the Daemonhost known as the "Fatewoven," which actually served as a mortal shell for Kairos Fateweaver who had masqueraded as Aforgomon.
• Baleq Uthizzar - Baleq Uthizzar was the Captain of the 5th Fellowship of the Thousand Sons Space Marine Legion during the latter days of the Great Crusade and the beginning of the Horus Heresy in the late 30th and early 31st Millennia. He obtained his rank following the death of Captain Apophis during the bloody Kamenka Troika Campaign against the Orks. Uthizzar also served as the XV Legion's Magister Templi of its Athanaean Cult. Following the Council of Nikaea where the Emperor proclaimed a Decree Absolute against the use of psychic powers and the continued forbidden study of the arcane, Magnus continued to dabble with forbidden knowledge despite his father's decree. When the Thousand Sons' Primarch failed to save the Warmaster Horus' soul from being corrupted by the Ruinous Powers, he utilised his own psychic abilities to get a message to the Imperial Palace on Terra by directly contacting the Emperor mind-to-mind, though this ruptured the Palace's considerable psychic defenses and killed thousands of people whose minds were unable to handle Magnus' potent psychic call. But the Emperor refused to believe that His favorite son Horus would ever betray His trust and so He assumed that it was Magnus who had been corrupted by the Chaos Gods since he was once again using the sorcerous powers that had been banned by the Council of Nikaea. Believing that Magnus sought to sow dissension in the Imperium to serve his masters in the Warp, the Emperor ordered the Space Wolves Legion to go to Prospero and bring Magnus back to Terra. When Uthizzar accidentally discovered the inevitable attack by the Space Wolves by inadvertently reading his Primarch's thoughts, he was shocked that his gene-sire would withhold such information from his sons. Remorseful at his actions and resigned to his fate, Magnus could not allow Uthizzar to reveal the truth, and so killed him with his powerful psychic abilities.
• Apophis - Apophis was the Captain of the 5th Fellowship and Ahriman's oldest friend. Apophis, along with the 5th Fellowship, were wiped out during the bloody Kamenka Troika Campaign against the Orks.
• Khalophis - Khalophis was the Captain of the Thousand Sons' 6th Fellowship during the latter days of the Great Crusade and the beginning of the Horus Heresy in the late 30th and early 31st Millennia. He also served as the Magister Templi of thePyrae Cult. Khalophis was present during the Burning of Prospero, when the Space Wolves Legion, accompanied by elements of the Legio Custodes and the Sisters of Silence, were sanctioned by the Emperor of Mankind to punish the Thousand Sons Primarch Magnus the Red for his blatant violations of the Imperial Decree Absolute rendered during the Council of Nikaea forbidding the use of psychic powers and the pursuit of sorcery. During the defence of his homeworld, Khalophis sent his consciousness into the inert Battle Titan Canis Vertex, that stood sentinel before the Pyramid of the Pyrae Cult. Initially, the now-living Titan seemed to turn the tide of the battle, but ultimately, Khalophis' victory was short-lived as he was caught in the tremendous explosion of pent-up aetheric energy released by the dying Phael Toron. Khalophis fought to sever his connection to the doomed war engine, but the aetheric feedback lashed back upon him, the fire consuming him utterly, and the entire pyramid of the Pyrae exploded in a searing fireball of glass and steel.
• Phael Toron - Phael Toron was the Captain of the Thousand Sons' 7th Fellowship during the latter days of the Great Crusade and the beginning of the Horus Heresy in the late 30th and early 31st Millennia. He also served as the Magister Templi of the Raptora Cult. Toron was present during the Burning of Prospero, when the Space Wolves Legion, accompanied by elements of the Legio Custodes and Sisters of Silence, were sanctioned by the Emperor of Mankind to punish the Thousand Sons Primarch Magnus the Red for his blatant violations of the Imperial Decree Absolute rendered during the Council of Nikaea forbidding the use of psychic powers and the pursuit of sorcery. During the defence of his homeworld, Toron, like many of his fellow Battle-Brothers, lost control of his Tutelary (Familiar) Dtoaa, who became his devourer and filled him with more power than the greatest master of the Warp could contain. Unable to control the pent-up Warp energy within his body, Toron died spectacularly when his body exploded with the violence of a newborn star.
• Auramagma - Auramagma was the Captain of the Thousand Sons' 8th Fellowship and a member of the Pyrae Cult. During the Scouring of Prospero, Captain Auramagma attempted to halt the Primarch Leman Russ' destructive rampage, and targeted the Lord of the Space Wolves directly with the full might of his sorcerous powers. Alas for him, Russ' indomitable will and the protections of the Rune Priests proved too strong, and while Auramagma managed to forcibly halt the Primarch, the backblast of his psychic assault incinerated him on the spot.
• Amon - Amon served as Magnus' tutor before the arrival of the XV Legion on Prospero, and he became one of the Legion's first Prosperine Astartes at the direct invitation of Magnus. Amon eventually rose through the ranks to become Captain of the Thousand Sons' 9th Fellowship. He became the founder of the Corvidae Cult and its first Magister Templi. He also served as Equerry to Magnus, responsible for the Primarch's security and for officiating certain sorcerous rituals, amongst other duties. Amon would not only survive the battles of the Great Crusade, but those of the Horus Heresy as well, eventually becoming a member of the Cabal of Ahriman and vanishing from recorded history after Ahriman's exile from the XV Legion.

Source

• Codex Heretic Astartes - Thousand Sons (8th Edition), pp. 16-17
• A Thousand Sons (Novel) by Graham McNeill
• Prospero Burns (Novel) by Dan Abnett
• The Crimson King (Novel) by Graham McNeill, Ch. 23