"The Omnissiah filled the galaxy with mysteries so that we might learn from them, coming step by step closer to his perfect being. To ignore them, even in the face of war, is heresy."
- – Archmagos Belisarius Cawl
"His colleagues are limited. Their beliefs have become a faith that they dare not challenge. The Adeptus Mechanicus is far more trammelled in its thinking than the Mechanicum of your time was, my Lord Guilliman, and the archmagos was a radical in those distant centuries. You would not have come to him if he were not."
- – Cawl Inferior, Cawl's not-an-AI
"I suppose I could part with one and still be feared"
- – Cawl, on his various Doomsday Devices
Archmagos Dominus Belisarius Cawl is the first unique character for the Adeptus Mechanicus faction, and like all good servants of the dragon on mars has turned himself into a FUCKING CYBORG. Along with Inquisitor Greyfax and Saint Celestine, he forms the Triumvirate of the Imperium. This motherfucker is old. How old? Ten thousand years, old enough to have been one of the tech-priests that aided the Emperor of Mankind in designing the Black Carapace. Which should be impossible as the oldest a magos of the Mechanicus can get is around 1,000 years and they also go insane, but who knows. He might have spent most of it in stasis, or built himself new bodies and implanted his not-an-AI into it, but the most popular rumors among the Mechanicus have it that he did so using some kind of forbidden xenos tech while replacing what few organic parts he had left with machinery, Ship of Theseus style. Even after having his memories wiped on two separate occasions, he's famed among the AdMech as having a truly unmatched hoard of knowledge compiled over the millennia.
He has some sort of mysterious mission he's been on for the last ten thousand years. It was given to him by /tg/'s favourite person, apart from a certain Spiritual Liege and consists of two parts. The first is making Guilliman a brand new suit, making Belisarius Cawl the slowest tailor in all of fiction (though admittedly that's because it went on hold until he could figure out the 'resurrection' thing). The second is to build brand new weapons and pull out old ones to help fight against the enemies of the Imperium. His main creation was the Primaris Marines which took him nearly 10,000 years to create (although this is because how ridiculously advanced the Emperor's work was so hard to decipher). Or he's just incredibly lazy. It's not like he really answers to anyone.
His voice has varied somewhat, the few times we've heard it. In the trailer for Rise of the Primarch he also sounds like a combination of Mr Freeze (TAS version) and a Dalek. However, in the more recent trailer for Battlefleet Gothic: Armada 2, detailing Cawl's arrival on Cadia and his meeting with Trazyn Cawl's voice is damn near incomprehensible. It's a wonder anyone could have a conversation with him.
On a side note, his name is most likely a shoutout to this guy, who basically made the Byzantine Empire great again, if only for about a dozen years. As an elegan/t g/entleman or a clever ca/t g/irl you already knew the Byzantine Empire is, in fact, the Eastern Roman one, with both of the terms created after the end of the realm; its citizens referred to it as the Roman Empire - the very one which the Imperium is based on.
During the Horus Heresy
Cawl's first recorded appearance in history was as a Tech-Acolyte on the Trisolian system during the Horus Heresy; while he had declined several of the more visible cybernetic augmentations favored by the tech-priests, he had secretly undergone illegal brain-enhancing surgeries to make himself smarter. Even back then, he had a reputation as a maverick for his pro-innovation stance.
When Horus and his Legion attacked the world of Trisolian A4, Cawl's master defected to the traitors for fear that her secret project to make herself immortal via cloning would be lost. Cawl feigned loyalty to the Warmaster, and later took the opportunity to kill his treacherous superior when Leman Russ and the Space Wolves arrived to try and kill Horus. After absorbing her intelligence core and knowledge of cloning, that is.
Fall of Cadia
Cawl is introduced at a technoarchaeological dig on the planet Eriad IV, a planet only notable for having a small Imperial outpost that was destroyed in a Black Crusade. Although his progress is interrupted by an Orkish invasion, he continues onward, following the mysterious hints of the Shadowseer Sylandri Veilwalker. Eventually, he digs deep enough to find the remnants of ancient obsidian pylons. Cross-referencing this with similar discoveries, he realizes that Abaddon has made a point of destroying similar such pylons across his Black Crusades. He puts two and two together, and immediately starts heading for Cadia, fearing that they might be the last pylons left in the galaxy.
After arriving at Cadia and briefing the command about his discoveries, he went about studying the pylons, believing that they held the key to Abaddon's defeat. This was a dead end until Trazyn showed up and gave him some Necrontyr tech-support. With his help, he managed to activate the true power of pylons, shrinking the Eye of Terror and fucking up all warp activity on Cadia. This was a double-edged sword, as while it prevented Daemons from manifesting, it also forced the Legion of the Damned out of the Materium and greatly weakened Saint Celestine. Despite this, the defenders successfully got the Black Legion to retreat, and victory looked inevitable.
Then Abaddon just had to crash the remnants of a Blackstone Fortress into Cadia. Cawl's efforts were for naught, as the pylons were destroyed and the Eye of Terror expanded to consume the Cadian Gate. He retreated on his Ark Mechanicus, the Iron Revenant, but was pursued by Abaddon, who just learned of a mysterious relic Cawl had and sought to claim it for himself. Cawl was forced to sacrifice the Iron Revenant to stave off the Vengeful Spirit and took his artifact along with the rest of the Imperial forces to the ice moon of Klasius, where they found the Emprasword. Cornered by the Black Legion, all seemed lost, until they were saved by the timely intervention of the Ynnari Eldar, who offered an escape route through the webway and an alliance (needless to say, he is really ashamed that he couldn't stop what happened to Cadia).
Rise of the Primarch
This is where it's revealed that the artifact Belisarius has is the Armor of Fate and a self-fitting dressing room, commissioned by Grandpa Smurf several millennia in advance. Cawl, alongside the Ynnari, successfully uses this to resurrect Guilliman and then assists him in his crusade to Terra. When they arrive Guilliman tells Cawl to work on the second part of his mission, that of strengthening Imperial forces by pulling out all the stops on Mars.
It has since been revealed that this "second part" was the creation of the Primaris Marines, along with their new wargear.
What Could Possibly Go Wrong?
Cawl currently wants Guilliman to appoint him Fabricator General of Mars so he can "Get Shit Done", but Guilliman is unwilling to have all of the tech priests lose their minds over it; given his outspoken views on the value of innovation and thinly veiled contempt for the accepted AdMech dogma such a promotion would be certain to result in a civil war within the Mechanicus.
Demonstrating what could generously be called a disregard for consequences, Cawl also has experimented with creating Primaris Marines of all the Traitor Legions, as well as the infamous missing Legions II and XI. He petitioned Guilliman to sanction their use, but you can guess how that went. (Guilliman has a feeling that he's just going to try and make them anyway). He is also trying to make new pylons to shrink back the Great Rift; perhaps it's time for Cawl to pay a visit to Illuminor Szeras, or maybe politely request (at gunpoint) Magos-Explorator Omnid Torquora to tell him all the knowledge he has left of that empyrical bomb he used in the novel Adeptus Mechanicus: Tech-Priest.
Oh, and that AI we mentioned in the top quote? It's not even the only one. Guy Haley's In the Grim Darkness of the Far Future openly mentions that Cawl's mind is essentially composed of numerous AI copies of himself operating in tandem with his original mind, in what he compares to being a conductor of an orchestra with the AI copies as the musicians. Which in effect makes him practically immortal, since he could switch on a backup copy of himself if his original body dies.
On the Tabletop
Come with a special rule that allows you to add or subtract 1 when rolling on the Canticles of the Omnissiah which as Mars you get to roll twice and keep both, allows Mars units within 6" to re-roll any to hit in shooting,also have the ability to repair any friendly imperium model within 3" by 1 wound, without caring even a little bit about its other keywords - he can repair infantry, cavalry, whatever. AdMech units get d3 wounds healed instead, though. I guess 10000 years of min maxing yourself lets you do these things. And his Solar Atomiser is an Assault D3 S10 AP-4 unholy beast that does D3 damage, unless the target is within half range, which then it does D6 damage.
Belisarius Cawl is quite a formidable opponent. His ranged weapon of choice is the melta-gun on steroids Solar Atomizer, and for melee he's got a Mechadendrite Hive to fight hordes, Arc Scourge to fight vehicles, and a power axe to fight terminators. He also brings across the three Canticles of the Archmagos, which are like the Canticles of the Omnissiah but they also affect friendly vehicles not part of the Cult Mechanicus faction. Harmony of Metallurgy gives It Will Not Die, Utterance of Neutralization increases Ballistic Skill, and the War Hymnal of Fortitude grants invulnerable saves.
Not only can he dish out the pain, he can take it as well, with a 2+ armor save, Toughness 6, Feel No Pain (which is rerollable if he's the Warlord), and five wounds which he restores 1d3 of each round. Oh, and he can also use his canticles to give himself three It Will Not Die rolls. However, he lacks Eternal Warrior, and his Invulnerable Save is a mere 5+, making him vulnerable to Instant Death.
Despite all his cheese, he'd probably still get beaten by Anacharis "I fuck Primarchs for breakfast" Scoria.
As mentioned, Papa Cawl is probably the only cogboy in the Adeptus Mechanicus (and probably in all the Imperium) who has straight-up invented loads of new shit without disappearing. Many of his new toys have features found in other xenos and/or look like their weapons. Whether or not it is an example of "borrowing" their designs or convergent invention is up to you. This list will certainly get bigger as more units are introduced.
From the Space Elves
- Primaris Reiver incorporate sonic/audio weaponry into their helmets to scare the shit out of their enemies, just like the howling banshees (though to be fair, we've invented such weapons in early M3) or Emperor's Children, though we're pretty sure he's not dumb enough to mess with Chaos stuff... we think. Night Lords have used such tech since the start of the Great Crusade. The Mechanicus would have made it for them even back then.
- The Overlord Dropship uses energy shields instead of the usual void shields.