Aerius is a Hive World of the Imperium, a mighty industrial world, and keystone to the Imperium's control of its sector. During the 38th Millennium it suffered a devastating plague. In the 41st Millennium, Aerius was once again smitten by a deadly plague, and as a result, millions died.
There had indeed been many strange portents. A great comet had appeared in the skies of Aerius, the baleful star of legend, which appears only once in every two millennia, and whose appearance always presaged doom. Showers of falling stars descended on the world at the moment of its appearance.
The plague was connected with the mysterious Black Pyramid, an impenetrable Aeldari psychic construct which was built, unknown to the local human population, to restrain a Greater Daemon of Nurgle named Botchulaz.
There is little official information on the founding of this Imperial world, but it is generally assumed that it was brought into Imperial Compliance during the Great Crusade sometime in the 30th Millennium. What is known (only by the Inquisition, of course) are the events surrounding the imprisonment of the Greater Daemon named Botchulaz.
Sometime during the 38th Millennium, Nurgle despatched Botchulaz to spread his pestilence and plagues amongst the crowded hive-populations of the Imperial Hive World of Aerius. Unbeknownst to the daemon lord, he had blundered into a well-executed trap set by the Aeldari. Led by their leader Farseer Kaorelle, the Craftworld Asuryani warriors dropped from the sky and attacked the vile daemon en masse. Kaorelle began the necessary ritual in order to bind Botchulaz, trapping the loathsome creature within the psychic construct known as the "Black Pyramid."
Unfortunately, the Aeldari were interrupted when they were attacked by Imperial forces before they could complete the ritual. Aided by the Inquisition, the Space Wolves Space Marines and a detachment of Galt Regiment Astra Militarum troops assaulted the Aeldari. During the ensuing melee, they seized the arcane Talisman of Lykos. As the brutal fighting continued, the talisman was broken into three separate pieces, rendering its powers dormant.
At the conclusion of the battle, the commanders of the Imperial forces divided their prize amongst themselves. One piece was taken by Inquisitor Darke of the Inquisition, the second piece by the senior Space Wolves commander and taken back to The Fang, and the remaining piece was given to Commander Byran Powys of the Galt Regiment to be taken back to his homeworld of Galt.
Botchulaz remained fettered within the Black Pyramid by multiple layers of arcane ward-pacts, Aeldari spirits and the Farseer's powerful incantations. These intricate patterns only revealed their flaw once every 3,000 Terran years when the comet Balestar became visible in the Aerian sky and Aerius' moons were in the proper alignment. Whilst imprisoned, the Great Unclean One was still able to communicate with his foul servants on a limited basis.
During his imprisonment, he eventually discovered the locations of each broken portion of the Talisman of Lykos. The daemon lord schemed to acquire these pieces so that he could free himself from his wretched prison. The return of the comet Balestar in the late 41st Millennium heralded dire portents for Aerius. This coincided with a deadly plague that had struck the Hive World, though this "coincidence" was actually helped along by the subtle manipulations of Botchulaz and his foul agents hidden amongst the masses of Aerian citizens.
Heeding the dire warnings of the Oracle of Chaeron, Inquisitor Ivan Sternberg turned to the Space Wolves for help in recovering the pieces of the ancient Talisman of Lykos which could cure the disease-ridden planet and restore order. This was to be the first mission of Ragnar Blackmane of Berek Thunderfist's Great Company as a Blood Claw.
Blackmane was assigned to assist the pair of Inquisitors, Ivan Sternberg and Karah Isaan, in recovering the Talisman. The Inquisitors had come to Fenris to request the aid of the Space Wolves in reclaiming the Aeldari artefact. Sternberg suspected that the Black Pyramid, a famous structure of the planet, which had been the site of the great battle of the Space Wolves, the Imperial Guard and the Inquisition against the Aeldari, could restore the planet. One piece of the talisman was kept in the Vault of Victory within The Fang, one was to be found on the planet Galt, and the third was lost in the Warp aboard a derelict Space Hulk.
Unknown to Inquisitor Sternberg, one of his servants, Commander Gul of the Inquisition vessel Light of Truth, was a Heretic and a servant of Botchulaz. Acquiring the first piece of the talisman from the Space Wolves, the Inquisitors and the Space Wolves set out for the world of Galt. When they arrived at the planet to recover the second piece of the talisman, they found that an Ork horde had invaded the system and that the Greenskin Warlord Gurg had taken possession of the piece of the talisman found on Galt. Ragnar and his companions infiltrated the Ork horde, and battled against the Greenskin Warlord to reclaim the second piece of the Talisman.
Inquisitor Isaan then used her psychic abilities to discover that the last piece of the talisman was aboard a Space Hulk, near the dead sun of Korealis. Ragnar and the Inquisitor successfully recovered the final piece of the talisman after battling the myriad dangers, such as Tyranid Genestealers, found aboard the drifting Hulk.
After acquiring the final piece, the Talisman of Lykos was now whole. When the group of Imperials travelled to Aerius to use the talisman, they found nearly the whole planet had already been infected by the plague. Taking the arcane item to the central chamber of the Black Pyramid, before they entered the structure they were warned by what appeared to be an Eldar spirit (in actuality a hologram) not to use the device. The Inquisitors and their Space Wolves escorts ignored the warning.
When Inquisitor Sternberg activated the talisman they unwittingly released Botchulaz from his imprisonment, much to the shock of the Imperials. The gloating Great Unclean One recounted his tale of how he came to be imprisoned within the psychic construct, then proceeded to explain that they had been manipulated to do his bidding all along. Calling forth his minion Commander Gul to receive his reward for his faithful servitude, Ragnar Blackmane quickly drew his Bolt Pistol and shot the corrupt officer through the heart, killing him.
Inquisitor Isaan then boldly attacked the Greater Daemon with her psychic abilities but Botchulaz mortally wounded her. The daemon lord reanimated Gul's corpse, ordering the revenant to kill the intruders. Tapping into the collected psychic power of the Black Pyramid, Botchulaz began casting a grand spell of archaic power, animating millions of the planet's plague victims as Plague Zombies.
Inquisitor Sternberg and the Space Wolves valiantly fought the Greater Daemon, distracting the loathsome creature long enough for Isaan to siphon the power of the Talisman of Lykos in order for her to seal the Black Pyramid, sacrificing herself in the process and trapping Botchulaz within for another 3,000 standard years.
- Ragnar's Claw (Novel) by William King