Archon Katukaur (the first of the undescribable) rose to his ranks from being a deformed kabalite warrior, created by a haemonculus's wrack of curiosity. The warrior wore heads of catachan elites, who he had butchered himself. Other warriors and archons were ashamed to accompany the warrior, who's body was pierced by tubes that pump drugs through him, keeping him alive.
On a raid (933.M38) he and a large group of wracks who envied his ranks, planned a lesson that would give them respect in the Kabals and covens of the dark eldar. They hid in the shadows of towering, hunched alterations of volunteers that gave themselves to the haemonculi's work top, and leaped upon cadian elites known as the "Eldar Killers". Every man taught a gruesome lesson by grotesques and scourges, that were under the astonishing command of the altered kabalite warrior. They followed his orders, muffled by his wrack helmet to hide his hideous face. They severed limbs at his command, chopping at arms and heads, leaving the last if the Cadians confused at the bizzarre fashion of murder. The eyes of the catachans rolled around in their sockets that hung from the warriors neck as he lashed at terrified elites that watched the heads of their buch cousins stare back at them. This was a battle unlike any before.
When all of the imperial guard had been decapitated, the wracks shackled the near dead Cadians and brought them back to cammorragh, where they were released to rome the streets of the dark city. Archons saw the eldar killers and watched them bump into each other, before a hellion gang put them out of their misery.
Nobody heared from the warrior again, and presumed he was killed from his deformities.
They remembered him as Katukaur , which means "the first of the undescribable".
He lurked in the shadows of cammorragh, where the decapitator watched the pale catachan heads.
He studied dark magic of necron orbs from the lone mandrake, and summoned dark fears from a realm in a worse state than the lower levels of the dark city. He watched the mandrake's coloured fire twirl around his black skin. He watched him polishing his collection of skulls: tyranid, ork, human... And humanoid. The puzzled warrior watched him clean an archon's helmet of blood, and take out a head from inside it.
"A'klodre dek'l grunde cea kaechmuar, un'd heaarkh Labanh uriek iin' Arkande inndraen." - "in order to become the power, you must take the life of those in power of you." He told him, and the warrior saw the rise of a coven come to him from the pits of the darkest realms.
The warrior stripped his helmet and armour from his body, and replaced them with cloaks and mandrake powers, and assassinated each and every archon that had ever looked Down on him, before retiring to the decapitator, full of energy and power from the pain he had caused in cammorragh. News spread, and slaves were taken, the work of a descendant of slaanesh or a rebel gang of orks, none suspected Katukaur, the undescribable.
The warrior accompanied covens of great power and led troops of warriors, which led to leading troops of wracks, of grotesques, until he the rise of of the warrior was complete:
Katukaur became an archon of a different scheme.
He was always different, lurking only in mandrake realms and haemonculi halls of meat, the archon became the leader of a coven of the wracks, grotesques, and scourges he took on The Gruesome Lesson in M38, joined by razorwing jetfighters and a ghostly pack of mandrakes at his side, sommoned by the one who takes heads, the decapitator. It is believed that archons fear him and it is rumoured that even asdrubael vect, supreme overlord of cammorragh keeps away from the haemonculi's operation chambers for more than his pride for Kabals only.
In battle, the archon studies his haemonculus and his creations under the shadow of several grotesques that roar muffled chants that the imperium fear. However in cammorragh, he chooses to practise magic in the depths of the dark city, beside mandrakes and mindless wracks.