The Mantis Warriors, originally known as the Mantis Legion, are a Loyalist Space MarineChapter believed to have been Founded as part of the 8th Founding in 598.M35, created to help relieve the White Scars in monitoring and countering the many threats harboured by the MaelstromWarp Storm in the Ultima Segmentum. In the early 900's.M41, they found themselves on the wrong side of the Badab War, and were forced to give up their home world and pursue a 100 year penitent crusade to seek the Emperor's forgiveness. After a century, they are no allowed to recruit new battle-brothers after having proved their loyalty, when they played a critical role in throwing back a Tyranid splinter fleet from the strategically-placed Imperial world of Herodian IV.
The Marauders are a Loyalist Second Founding Successor Chapter of the White Scars according to the Apocrypha of Davio, written in the 33rd Millennium. Little else is known about them in Imperial records save that the Mantis Warriors Chapter, which grew infamous during the Badab War, was created from the gene-seed stock of the Marauders.
The Marines Errant are a Loyalist, fleet-based Space Marine Chapter of unknown origin created late during the 23rd Founding in the 37th Millennium, to repair the gap left in Imperial military forces by the loss of other Chapters. Further details of this Chapter's origins can be found in the Mythos Angelica Mortis, the great work concerning the Space Marines of this age, which lists five such new-founded Crusade Chapters and their blood-progenitors, with the Marines Errant recorded as having the Eagle Warriors Chapter as their immediate forebears. The Eagle Warriors' gene-seed was drawn from the Ultramarines' lineage, although why the Eagle Warriors in particular were singled out for the honour of a "named" Founding being drawn from their ranks at this time remains lost to posterity.
The Marines Exemplar are a Loyalist Space Marine Chapter created from unknown origins and Founding. They are one of the Chapters founded to make up the Astartes Praeses, the twenty Chapters created to guard the regions surrounding the Eye of Terror. Nothing else is known about this Chapter in current Imperial records.
The Marines Malevolent is a Loyalist Space Marine Chapter founded in the 32nd Millennium, and are of unknown genetic origin. While loyal to the Emperor of Mankind and deeply dedicated to the eradication of all of the Imperium's enemies, they have at times shown a disturbing and callous disregard for the lives of the civilians of the Imperium as long as their mission objectives are obtained, which has brought them into conflict with the Salamanders Chapter as well as many other Imperial organisations, including the Inquisition. The Marines Malevolent take a flippant view in regards to collateral damage and the use of excessive force. If innocent civilians or other Imperial forces happen to die due to their brutal tactics, then so much the better. This Chapter believes there is no such thing as "innocence," simply varying degrees of guilt, and that people who will not fight to defend themselves have no right to live as their freedom was purchased with the blood of others more worthy of the Emperor's blessings.
The Marines Vindicant are a Loyalist Space Marine Chapter of unknown origin and Founding. Almost nothing else is known about the Chapter in Imperial records save that they played a major role in the scouring of the world of Vorlinghast in 981.M41, which had been overrun by Plague Zombies and the Death GuardTraitor Legion.
The Mentors, sometimes referred to in Imperial records as the Mentor Legion, are a Loyalist Codex Astartes-compliant Space Marine Chapter of unknown origin created during the 26th Founding in 738.M41, making them one of the most recently Founded Chapters in the Imperium of Man. Little is known about this Chapter in Imperial records, though the Mentors are known to be a reclusive and suspicious Chapter of Astartes who no longer trust other Space Marine Chapters or the Imperial government, preferring to work alone and unobserved by all save the foes of Mankind and the Emperor.
The Metamarines are a Loyalist Space Marine Successor Chapter of the Ultramarines created during an unknown Founding. The most renowned action of the Metamarines was their participation in the 13th Black Crusade in 999.M41, where they aided other Imperial forces in the defence against Abaddon the Despoiler and the Forces of Chaos unleashed upon the world of Cadia and its surrounding sectors.
The Minotaurs are a savage Loyalist Space Marine Chapter whose actual origins and Founding remain unknown. The Space Marine formation by this name at large in the Imperium today appears to bear little resemblance to accounts of its past. That there existed a Loyalist Space Marine Chapter called the Minotaurs, created during the 21st Founding, known as the "Cursed Founding," of the 36th Millennium, is not widely contested in the Imperial record, but whether or not they are the same as the Chapter bearing the name that took part in the suppression of the Macharian Heresy in the opening decades of the 41st Millennium and the same Chapter that would later go on to play a crucial and bloody role in the Badab War and the Orphean War is not so certain. The Minotaurs possess a reputation for being unusually xenophobic Astartes, even for the Imperium, as well as often unreliable combatants who do not work well with other Imperial military units.
The Mortifactors are a Loyalist, Codex Astartes-compliant Second Founding Primogenitor Chapter of the Ultramarines founded during the 31st Millennium. The Mortifactors recruit from the austere Feral World of Posul, where the sun never rises on its frigid plains and its population of nomadic tribes are constantly in conflict with one another and practice cannibalism. The Mortifactors' Neophytes are chosen from the most vicious and skilled warriors on the planet -- who subsequently have a very morbid and dark outlook on life
The Nemesis Chapter is a Loyalist Codex Astartes-compliant Space Marine Chapter. They are a Second Founding Successor Chapter of the UltramarinesLegion. There is little information on this little-known Chapter in current Imperial records, except that they are descended from those Ultramarines companies who fought alongside the then-Loyalist Night Lords Legion during a brutal purgation campaign against Abhuman corsairs during the Great Crusade. Afterwards they bore black gauntlets, midnight blue helms and the ancient weighing scales and death's head icon of judgment in heraldic opposition of their Legion numeral, and took the name of "Nemesis" as their own. During the Second Founding, the existing "Nemesis" companies formed the core group of Astartes for the newly formed Nemesis Chapter.
The Night Watch is a Loyalist Space Marine Chapter created from unknown origin and Founding. This Chapter is one of the Chapters founded to make up the Astartes Praeses, the twenty Chapters created to specifically guard the regions of the Imperium surrounding the Eye of Terror. Nothing else is known about this Chapter in current Imperial records.
The Novamarines are a Second Founding Primogenitor Chapter of the UltramarinesLegion. The Novamarines are scattered throughout the galaxy fighting against the various enemies of mankind, and have not fought together as a Chapter since the early years of the 37th Millennium.
The Obsidian Glaives were a Second Founding Successor or Primogenitor Chapter of the Ultramarines. The Obsidian Glaives were recorded as having been annihilated when their home world of Obstiria was invaded in 998.M41 by the vast greenskin hordes of the infamous OrkWarlordGrukk Face-rippa and his Red WAAAGH!. Their current status is unknown.
The Patriarchs of Ulixis are a Loyalist Codex Astartes-compliant Space Marine Chapter. They are a Second Founding Successor Chapter of the Ultramarines. Proud Primogenitors, the Patriarchs of Ulixis have won great acclaim for their skill in battle. They are renowned for their exceptional bladework and marksmanship, to the point where their Veterans are often seconded to the Honour Guards of other Ultramarines successors.
The Prophets of Mercury were once a Loyalist Chapter of Space Marines of unknown origin and Founding. They were lost after entering the Eye of Terror in 321.M37 as part of the disastrous Abyssal Crusade. It is unknown what they endured during their sojourn into the Eye, though they were declared Martyr Extremis in absentia by the Imperial Inquisition, considered to have been wiped out by the Forces of Chaos.
The Purple Stars are a Loyalist Space Marine Chapter of unknown Founding and origin. Almost nothing is known about this Chapter in current Imperial records. They are rumoured to have close ties with the Adeptus Mechanicus and the Inquisition.
The Rainbow Warriors are a Loyalist Space Marine Chapter known to be a Successor Chapter of the Ultramarines, created during an unknown Founding. There almost no further mention of this obscure Chapter in official Imperial records. The Chapter's homeworld is called Prism. It should also be noted that in official Imperial records of Space Marine Chapter Homeworlds, this map displays the galactic locations of the various Space Marine Chapter Homeworld. But in the case of the Rainbow Warriors Chapter, instead of displaying their planet with the Chapter's name, it simply says, "record deleted." By looking closely, it is clear that the Chapter badge of this deleted Chapter is that of the Rainbow Warriors. This Chapter's current status is unknown.
The Rampagers are a Loyalist Space Marine Chapter and a Second Founding Successor Chapter of the White Scars. Like their progenitors, the Rampagers make use of ritual facial scarring to denote both the rank and achievements of Astartes in the Chapter. These scars are applied during a long, sacred Chapter ceremony called the Blooding. The blood drawn from the faces of the Space Marines during this ritual is then mixed with the drinks served during the feast that always follows the completion of the ceremony.
The Raven Guard is one of the original First Founding Space Marine Legions and was originally the XIXth Legion before the Second Founding and the adoption of the Codex Astartes. Their Primarch was Corvus Corax (a name which is a play on the Latin binomial species name for raven, corvus corax). The Raven Guard's homeworld is the planet called Deliverance, the airless mining moon of the Forge World Kiavahr, though its original name, before the Horus Heresy, was Lycaeum. The Raven Guard's fortress-monastery on Deliverance is known as the Ravenspire. The Raven Guard are known for their cool-headed, even intellectual temperament, their superb infiltration skills and skill at furious close-quarters engagements. The Raven Guard are the masters of unseen and guerrilla warfare, only engaging in frontal assaults when no other option presents itself. The Raven Guard is also rightly feared for the potent units of Assault Marines they field, who use a pair of Lightning Claws instead of the usual Bolt Pistol and Chainsword.
The Raven's Watch is a little known Loyalist Space MarineChapter of unknown Founding or origin. Very little is recorded in official Imperial records, with the exception of their most recent defence of the beleaguered world of Kitab in 990.M41, which came under attack by Tyranids, a splinter of Hive Fleet Eumenides.