The 8th Founding of Space Marine Chapters allegedly occurred during the mid-34th Millennium, undertaken amid the dark times of the Nova Terra Interregnum, when the Imperium of Man had been split into twin interstellar empires. Denouncing the High Lords of Terra, the Ur-Council of Nova Terra claimed rule over the Segmentum Pacificus. This period of divided rule lasted for nine standard centuries. Few records remain surrounding this Founding, but one of the earliest extant records likely to pertain to one of the Chapters Founded during this period is the Mantis Warriors which can be found in the Libris Gloriana -- a 777 volume treatise on the state of Imperial power commissioned for the ascension of High Lord Gogol after the Nova Terra Interregnum in 093.M36. It mentions in bombastic terms a Chapter of the Adeptus Astartes that is a "... warrior legion of the Mantis (or 'prophecy', the language is unclear)" of the 8th Founding (which would place its origins in the mid-34th Millennium) of "... the line of the great Khan, by his sons the Marauders." The text goes on to praise their successes in combating the Traitors of the Eye of Terror, as well as crushing alien threats, and speaks of them as operating far from home but fails to name their Chapter homeworld or state the star system in which it is to be found.
Another Chapter believed to have been founded during this time is the now nearly-extinct Angels Revenant Chapter. Noble if aloof by reputation even for the warriors of the Adeptus Astartes, this Chapter of the 8th Founding, and of the proud lineage of the Ultramarines, had spent much of its long history on crusade throughout the western Imperium. After its glorious role in the Orphean War of Faith, the Angels Revenant was given home at Libethra within the Orphean Sector. As stern supporters of the Ecclesiarchy and the Imperial Creed, the bounty of the Orphean Ministorum was given freely to the construction of the Chapter's Fortress-Monastery, while the hardy Feral World inhabitants of Patara formed the basis of new generations of Neophytes for the Chapter. While completely autonomous of sector authority they served as protectors, guarding the pilgrimage routes of the Cold Veil, while their Chapter ships plied tirelessly the borders of the Hesod Nebula and the Barren Stars, hunting down and slaughtering xenos corsairs and marauders that had long made these trackless regions their lair.
Of the final fate of the Angels Revenant Space Marine Chapter, little can be said for definite. Such scattered and fragmentary evidence that has been uncovered about their final hour suggest unsurprisingly that they fought to the last against the overwhelming forces unleashed against them, the Libethra System being found littered with the radiation-ghosts of deadly void combat and spreading clouds of micro-wreckage. Furthermore, the ancient hull of at least one of the vast Necron Tomb Ships that were later sighted above Amarah held fresh scars consistent with the unique signature of Space Marine bombardment cannon strikes at extreme close range. Indeed it may be the case that such was the resistance the Angels Revenant put up that the invaders resorted to breaking through Libethra's crust and unleashing the planet's molten core to seal their fate conclusively. When news of the Chapter's martyrdom reached the Synod Tempestus a Segmentum-wide day of requiem was decreed, the bells of a thousand worlds tolling to mark their passing. It is through now that no more than a few hundred Angels Revenant, far from the Orephus Sector on crusade, perhaps survive.
Select 8th Founding Chapters
| Chapter | Successors of |
| Angels Revenant | Ultramarines |
| Mantis Warriors | Marauders |
Sources
- Imperial Armour Volume Ten - The Badab War - Part Two, pg. 64
- Imperial Armour Volume Twelve - The Fall of Orpheus, pp. 17-18, 21-23, 32-33