Thantos is a Dead World located in the Halo Stars on the border of the Segementum Pacificus that contains multiple rare metals that are dire to the Nova Terran war efforts. However this planet is also home to an enigmatic alien race known as the Filii Mea Est, or the Children of the Darkness. Thantos is a binary pair planet with its twin Thantos Minoris. The Eternal Legion and the Wyverns Eternal share a Fortress Keep on Thantos that is primarily used as a forward operating base that over sees the crusades into the halo stars.
The surface of thantos is ravaged by constant storms that start and sporadically alter through out its day. These storms when they start are often referred to as "Wraith Storms." These Storms strip the land of any living organism and revert the affected area back into a barren waste land, not even a Space Marine clad in power armour hopes to avoid such a fate. The Fortress Keep on Thantos is the only building standing that can hope withstand the ferocity of the Wraith Storms. The next notable future of Thantos is the caves that dot the surface. These caves house the remenants of the Filli Mea Est.