Grimmig is one of three moons orbiting the planet Adrilles. It is the largest of the moons with a equatorial diameter of 3,226 km. It completes an orbit of Adrilles every 15.945 days. With an orbit that never brings it closer than 1.2 million kilometers, Grimmig is also the moon furthest from its planet.
History – Necrons
Like Abfall and Brache, Grimmig was formed as a result of a war between two Necron dynasties millions of years before the Imperium existed. The largest chunk of rock torn from the planet would form the core of what would become the moon Grimmig. Within that core lay a tomb of the Sautekh dynasty and within that tomb lay the dynasty’s leader.
History – Imperium
Grimmig was home to mining operations. Its surface was rich with ore, which was transported back to Adrilles to be processed and used in the northern Forges. The moon had a sizeable defense force as well, but it was ill-prepared for Hive Fleet Leviathan¹. It was engulfed by the Shadow in the Warp² before any signal could be sent. Its silence was the only clue that something was terribly wrong on Grimmig.
The machinations of the Jager Corps woke the Sautekh dynasty on Adrilles and on Grimmig, which in turn woke the Rubicon Necrons within Abfall. While forces of the Sautekh dynasty were engaged on the planet’s surface, other arms of its might were formed on Grimmig. In fact, some historians aruge that Grimmig was the Sautekh Necrons’ primary base of operations and not the positions of strength established in the volcanic north of Adrilles in the weeks following the Battle of First Contact. (Those same historians claim that the daemons of Khorne ruled the volcanic north.) The Sautekh Necrons certainly used Grimmig as a staging point for operations conducted on Adrilles. Eternity Gates were used to move Necron troops and Necron controlled Tyranids from the surface of Grimmig to Adrilles.
The Space Wolves Strike Cruisers orbitting Adrilles were scanning the moons and came to learn what was occuring on Grimmig. That information lead to the combined operation known as the Assault on Grimmig, which was designed to cripple the Sautekh operations on that moon. The operation failed. For a considerable time afterward, Grimmig was largely ignored by its enemies.
Tomb of Imotekh – The Tomb of Imotekh the Stormlord became operational when its lord was awoken by the machinations of the Jager Corps Psykers on Adrilles. The Tomb was where a pact was formed between the Sautekh Necrons and the forces of Chaos.
The Lost Tombs – The Cryptek Lay Arteb was tasked by Imotekh the Stormlord to take a sizeable force into the bowels of Grimmig to find Sautekh Tombs that had failed to rise. The Cryptek did find the Tombs, some of which had become home to Tyranids during Hive Fleet Leviathan’s razing of Adrilles and its moon many years earlier. Outnumbered, Lay Arteb returned to the surface and reported to Imotekh. The Stormlord and the Cryptek later returned to the Tombs with the Necron / Tyrnaid artifact obtained during the Battle of First Contact and were able to use its influence to exert control over the Tyranids.
The Refineries – Refineries were abundant on Grimmig during the time of the Imperium before Hive Fleet Leviathan. Many of those refineries– though badly damaged and no longer operational– were still filled with ore and were sitting near or directly on top of vast networks of mines. Many of those mines had filled with volatile gases in the years since the Tyranid scourge. During the Adrilles War, the Jagers, Tau, and Space Wolves attacked Grimmig in a series of a precisely timed assaults designed to set and detonate explosives at various refineries on the moon’s surface. The hope was that the simultaneous surface explosions would ignite the volatile gas filling the mines, causing enough sub-surface disturbances that the Sautekh Tombs (and thus the Sautekh Necrons) would be horribly mauled. The assaults (collectively called The Assault on Grimmig) failed.
Historical data provides context to the current struggles in our part of the 40K universe. If our campaign takes liberties with canon it does so for the benefit of our game and not as a slight to the work of Games Workshop and fans of 40K.
1 Hive Fleet Leviathan
2 Shadow in the Warp