Cawl, the last remaining disciple of this technology, maintained that the Emperor was the Omnissiah, which was the theological position of the orthodox Mechanicum, but disagreed with a great deal of the rest of Mechanicum dogma as he felt the true Quest for Knowledge was to pursue technological innovation rather than ritualistically and mindlessly maintain the Imperium's existing technology base. Cawl worked at a console made entirely of light. Shifting displays of glyphs hung over him. His servo-skulls had come out of their hiding places in his body and hovered still in the air, data pulse beams linking Imperial technology with that of the ancient dynasties… After battling Orks who had been drawn to combat on the empty world with the powerful Mechanicus fleet, he recovered an ancient Necron artefact. He also learned more about the nature of the Cadian Pylons originally built by the Necrons that were tasked with restraining the eruptions of the Immaterium -- especially the Eye of Terror -- into realspace. Cawl had argued what would be the difference if the primarch replaced one more lord? But Guilliman argued that the Imperium did not exert such authoritarian political control over Mars, in accordance with the tenets of the ancient Treaty of Mars, that the primarch could appoint his own fabricator-general, and the other Tech-priests would never accept it even if he could. Cawl's first confirmed appearance in Imperial history came during the Horus Heresy, where he was a Tech-acolyte on the Mechanicum world of Trisolian-A4 in the Trisolian System. He was trained under the Magos Domina Hester Aspertia Sigma-Sigma, herself a master of the art of "soul-merging," essentially the digital duplication of another being's mind and psyche and the ability to merge it with another using cybernetic implants. His greatest friend and companion at this time was his fellow Tech-priest Friedisch Adum Ship Qvo.

Codex Adeptus Astartes - Space Marines (8th Edition), pp. 10-11, 19-21, 30, 41, 45, 53, 87, 98, 105It is during such times that Cawl dons the mantle of archmagos dominus, gathering about him Skitarii Legions and maniples of the Legio Cybernetica. Although Mars is his homeworld, other Forge Worlds often place troops beneath Cawl's command, asking only that he shares any knowledge accumulated. By the end of the first phase of the Indomitus Crusade just before the start of the Plague Wars, a small faction of devoted Mechanicus Tech-priests had formed around the archmagos. They served as his obedient servants, eager to aid him in the pursuit of this radical new course called "innovation."

One was located aboard Roboute Guilliman's ancient flagship Macragge's Honour, secreted deep within the bowels of the mighty vessel, hidden within a chamber where none were allowed to go but the primarch himself, and by Cawl's invitation only. A similar device was installed on Cawl's own Ark Mechanicus, the Zar-Quaesitor. God Is Evil: It is heavily implied that the Omnissiah is not an aspect of the Emperor ( not that he is necessarily "good" either mind) but in reality the ancient C'tan god known as the Void Dragon, meaning that they are unknowingly worshiping one of their most dangerous enemies. The archmagos handles this equipment as if he were born to it,’said Felix. ‘I assume that is a jibe,’ said Primus, striding forwards. ‘The archmagos works for our betterment.’ Well, not nothing,’ said Cawl, upping the volume of the voxmitter built into his face piece to maximum to be heard over the tumult. Cawl hoped to use this information to eventually find a way to build a technological solution that would seal the Great Rift once and for all.

Anti-Magical Faction: While most Tech-Priests dislike psychic abilities due to their unscientific nature, the sub-cult known as the Teeth of the Cog take this to the extreme, considering even Astropaths, Navigators and Sanctioned Psykers to be abominations that should be wiped from the galaxy despite how necessary they are to the survival of the Imperium. Members of this sub-cult actively seek out archeotech that could wipe out anything touched by the warp. The Emperor explained to the future Cawl in the memory that it would be his responsibility to continue His work, and must continue to do so even on the day that Cawl came to believe that he had betrayed all that the Emperor stood for. The very idea of betraying the Emperor horrified the young Cawl. During that span of ages the Tech-priest has served Mars and the Machine God as a Forge Lord and a Lexico Arcanus, but it is in his role as Magos Biologis that Cawl's greatest mastery lies. It is rightfully said that the aged archmagos dominus has forgotten more knowledge, particularly about genetics, than all but the most studious could ever hope to learn. Nearly completed, the gene-forged Primaris Space Marines lie in stasis, waiting to be awakened from their long slumber.

While gifted mechanics and craftsmen, Adeptus Mechanicus orthodoxy holds that all technological advances have already been discovered, and they therefore place more emphasis on reverse-engineering or recovering old knowledge than they do on experimentation or upgrades. Thus, the Mechanicus has kept mankind's technology working for ten thousand years, but has made little to no technological progress in that time. In fact, they have actually regressed, making some starships, weapons, and other devices irreplaceable because the Tech-Priests don't know how to build them any more. They are a parallel to medieval craftsman's guilds in the way they preserve skill but quash innovation with a monopoly on technology. Does Not Like Magic: The majority of Tech-Priests have an inherent mistrust, at best, of psykers and Psychic Powers in general due to their inherent illogical nature. The 8th Edition rules represent this with the Mechanicus specific Tactical Objective "A Victory for Logic" that grants the Adeptus Mechanicus player extra Victory Points for killing enemy psykers. With Guilliman resurrected, the Primarch drove the invaders from Ultramar before deciding to make his way to Terra through the Warp anomalies roiling the galaxy to an extent not seen since the Horus Heresy. Cawl joined the Primarch on this Terran Crusade, his technological acumen and combat prowess aiding the Imperial forces of the Crusade in all their trials and tribulations in the Warp rift known as the Maelstrom. Cargo Cult: The Adeptus Mechanicus' worship of technology is completely literal, and they attend their machines with prayers as much as with tools. Cawl was born on Mars, created in the birthing facilities of Xanthe Terra controlled by Magos Biologis Hammareth at some point during the early 31st Millennium. Like most Martian children he was vat-born and at the time of his birth already was physically and mentally a young adolescent. However, unlike most Martian children, he was able to speak normally at the time of his birth, a result of absorbing more fully the data uploaded into all Mechanicum fetuses while he was gestating.Belisarius Cawl is equipped with a Solar Atomiser, Arc Scourge, Master-crafted Omnisian Axe, Refractor Field, vast multitude of Mechandarites, and Servo-Skull. [2a] Cawl had requested on multiple occasions for Roboute Guilliman to instill him as the fabricator-general of Mars. As the lord commander of the Imperium and Imperial Regent, Guilliman had replaced five of the High Twelve of the Senatorum Imperialis upon assumption of the regency of the Imperium, and hundreds of the lesser high lords. The Extremist Was Right: Arks of Omen retroactively gives some grounds to their almost regressive stance towards innovation with the introduction of Vashtorr the Arkifane, a Chaos demigod empowered by craft and creation.

After reaching the Pharos, Cawl discovered that a shard of the C'tan Zarhulash the Potentate had provided the power source for the ancient Pharos. He forged a deal with the alien star god, in which Zarhulash agreed to destroy the device by removing its heart, creating a destructive miniature singularity. Empire with a Dark Secret: It is heavily implied that the Tech-Priests may be worshiping the C'Tan known as the Void Dragon, who is possibly imprisoned on Mars. The Emperor arranged things so their designs and beliefs were inspired by the Dragon without ever really focusing on it.There have also been references to other Heretek groups who don't worship Chaos but have rejected being part of the Imperium, finding it too stifling. Belisarius Cawl, Archmagos Dominus of the Adeptus Mechanicus, is the most brilliant mind alive. For 10,000 years he has furthered the cause of mankind, working under the aegis of the Emperor and Lord Commander Roboute Guilliman to prevent the inexorable march of the alien and the traitor. Many call him heretic, but all must recognise the magnitude of his achievements, for who else but he was entrusted to create a new generation of Space Marines? Cawl's knowledge of genetics gained from his soul-merger with Sedayne, along with the potent genetic material contained within the device known as the Sangprimus Portum, allowed Cawl to successfully complete the creation of the Primaris Space Marines and implement the Ultima Founding in ca. 999.M41, using candidates kept in stasis deep beneath Mars from the time of the Heresy until the 41st Millennium. This was the culmination of ten millennia of work intended to perfect the Emperor's creation. Colony Ship: During the Age of Strife, the Tech-Priests of Mars launched numerous colony ships into the void. Known as the Long March, many of the Knight and Forge Worlds scattered across the galaxy date from these voyages into the unknown. Belisarius Cawl is an old soul, both figuratively and literally. He has constantly been driven to create and achieve more. A fact that has simultaneously earned him adoration and criticism. Now, he's found yet another project worth diving into on the dead planet of Sotha.