The following is my submission for the Liber Martiale 2016 and the Brotherhood of Angels 2016. This is a preliminary version and is incomplete, for now, by design.
The Space Marines of the Adeptus Astartes are the mightiest warriors in the Imperium and their fury in battle is legendary. Few can stand against the might of a Space Marine Chapter and the foes of Mankind tremble at their name. But there are heretics and traitors within the Imperium whose evil threatens Mankind from within. To face such foes demands warriors whose hearts and souls are trained to withstand extremes of pain and terror, whose faith in the Emperor is as unwavering as it is strong. Since the dawn of the Imperium a brotherhood of Space Marines have fought these foes and defeated them. They are the Legio.
Starting in the days of the Second Founding, a number of Chapters maintained a loose alliance. This wasn't a formal alliance, but an unwritten agreement to communicate and cooperate insofar as they were able. Over the millennia, this alliance allowed a means of arbitration and cooperation among the participating Chapters. On numerous occasions this loose alliance prevented whole-scale battle between Chapters and allowed the Adeptus Astartes to police their own before the rest of the Imperium learned of wayward Chapters.
Over time, the Space Marines formalized the loose alliance that had existed for millennia. This alliance was known only to a few outside of the Adeptus Astartes. The alliance called itself simply "The Legio" as a symbol of their fealty to the Emperor and the legions of old. The Legio had several objectives:
- maintain bonds of friendship and loyalty among the manifold Chapters of the Adeptus Astartes
- serve as a means by which the various Chapters of the Adeptus Astartes may share tactical expertise and innovation
- keep an eye on the Imperium
- keep an eye on the various Chapters of the Adeptus Astartes
On the surface, the Legio is known most for the first two roles. In these, the Legio is also known as the “Collegium Astartes.” Chapters of the Adeptus Astartes will second individuals, squads, even whole companies to the Legio temporarily. During this period, these battle-brothers will interact with counterparts seconded from other Chapters, exchanging tactical information and ideas, even new developments in equipment (such as the Land Raider Crusader). Often, detachments will be seconded for specific training, and it is through these secondments that specific Chapters share their expertise with other Chapters.
A unique role within the Legio is that of the Herald. This role arose out of the Legio’s relationship with other Chapters of the Adeptus Astartes, which required the Legio to send emissaries when communicating with the other Chapters. A handful of Legio battle-brothers serve in this capacity, chosen for their purity and diplomacy. Some of these serve in the livery of the Mentor Cadres while others remain in the colors of their parent Chapters. These Heralds lead the delegations to other Chapters when the Legio seeks to weld temporary alliances between multiple Chapters for large-scale operations.
On occasion, the Legio will be granted a copy of a Chapter’s teachings – its version of the Codex Astartes or similar writings. The members of the Legio will then incorporate those teachings into its own records, the Librarium Astartes. It is thought that the Librarium Astartes is the most extensive collection of information on the organization, tactics, and accomplishments of the Adeptus Astartes anywhere in the Imperium.
A byproduct of the Legio's role in keeping an eye on the various Chapters of the Adeptus Astartes is the Legio's self-imposed mandate to hunt down traitor Astartes. Most Chapters are very reticent about revealing when any of their members turn renegade, so the Legio usually captures and executes traitor Astartes. On the rare occasion when a Chapter reveals information about renegades, however, the Legio is willing to work in concert with that Chapter and to turn captured traitors over to their parent Chapter.

The mobile star fort Arx Vigilans serves as the Legio’s headquarters. Able to service up to three Adeptus Astartes battle barges, twelve strike cruisers, and multiple smaller vessels, the massive construct rivals the famed Blackstone fortresses in size and firepower. Within the superstructure of the star fort can be found multiple training areas of sufficient size to allow for company-sized training evolutions, to include employment of vehicles. Of unknown provenance, some believe that it may be a remnant from one of the Legiones Astartes during the Great Crusade while others believe that it may be of more recent construction. Whatever its origins, the history of how the Legio came to possess it has never been revealed.

When a battle-brother is permanently seconded to the Legio, his actions, offices, and honors will be recorded in his personal heraldry. Upon his death, his personal heraldry will be crafted into two shields. Although the two shields are of different sizes and shapes, the honors crafted upon them by the Legio's artificers are identical and follow a complex heraldic scheme that is based upon the dictates of the Codex Astartes. The smaller shield is similar in shape and size to a combat shield. There are several different patterns of combat shield used by the Legio, so a battle-brother's death shield will be based upon the type of combat shield he used in combat or will be of a generic type. The larger shield is elongated in form and will actually serve as the cover for the sarcophagus that will return the battle-brother's remains to his parent Chapter. Both death shields will incorporate the battle-brother's honor shield into the center, though this will be a smaller version of the true honor shield and will be of carved brass.
The smaller death shield will be hung with the battle-brother's true honor shield in the Legio's Hall of Heroes, serving as a memorial to the battle-brother and a record of all the battle-brothers that have served the Legio over the years. The larger death shield will be used upon the battle-brother's sarcophagus and will be returned with the battle-brother's remains to his parent Chapter. The various Chapters of the Adeptus Astartes have different traditions with regard to the treatment of the death shield, though most display the shield within their equivalent of the Hall of Heroes. The return of the battle-brother's remains and the equipment that his Chapter granted to him when he was seconded to the Legio is of utmost importance to the various Chapters, and when the Legio is unable to return the battle-brother's remains for some reason it is customary to return gene-seed from the Adeptus Mechanicus stores on Mars.
Legio Ref. <Honour Shields>

The Legio spends considerable time training, serving as a vehicle by which the various Chapters of the Adeptus Astartes can share tactics, techniques, procedures, and equipment. In this, the Arx Vigilans serves as the training venue for many of the training evolutions at the company and below. When specific environments are required, or when the forces involved in the training require larger training areas, the Legio will utilize suitable worlds and interstellar bodies. While the Legio lays claim to several such locations, the vast majority are used only temporarily, with the Legio and forces to be trained traveling to those locations. Occasionally, other Chapters of the Adeptus Astartes may consent to their own worlds or training areas being employed for such use, but this is often only when those Chapters are participating in the training. More often, the Legio will evaluate the requirements for training and will locate a suitable world, moving on once the training is complete.
The Mentor Cadres usually serve as facilitators for training, providing instruction and serving as opposing forces when necessary. On occasion, other Chapters will serve in these roles, typically when they excel or specialize in the training to be delivered.

The Legio doesn’t have any specific combat doctrine, following the broad teachings of the Codex Astartes and the innovations shared by the Chapters of the Adeptus Astartes. Drawing from all Chapters of the Adeptus Astartes, the Legio possesses a great amount of flexibility. While an individual company or detachment might be trained extensively in a specific area based on the experience and desires of the commander, the overall combat doctrine of the Legio follows the Codex Astartes mandate of maximum flexibility.

The Legio is not organized into the Codex Astartes Chapter construct. The majority of the Legio’s strength in any engagement will consist of forces seconded from other Chapters. A small portion of the Legio’s force will be those battle-brothers that have been permanently seconded to the Legio, distinguished from the other Legio forces by their distinctive black and scarlet livery. These permanent Legio forces number roughly three hundred battle-brothers and are often known as Mentor Cadres due to their role. Often, Legio forces will identify as a “great company” based on one of the three primary oaths that they will swear before going into battle. The Blood of the Emperor is named for the sacrifices the Emperor made in order to see the Imperium created, and which he continues to make in order to perpetuate the Imperium; the Light of the Emperor symbolizes for the wisdom and knowledge the Emperor brought to the pockets of humanity that had been scattered throughout the galaxy, delivering them from the darkness of separation from the world of their origin; and the Justice of the Emperor represents the punishment the Emperor and his Adeptus Astartes deliver to the enemies of Mankind. Three Captains lead the Mentor Cadres and serve as the primary leadership of the Legio. They form the council that, with the leaders of the specialist orders within the Legio (the Chief Librarian, Reclusiarch, Master of the Forge, and Chief Apothecary), directs the overall efforts of the Legio.

Joining the Legio is for life, though most battle-brothers serve only temporary secondments by order of their parent Chapters. These temporary secondments serve as periods during which various Chapters share their tactical knowledge and teachings, training and operating together in service to the Emperor and the Imperium of Mankind. A rare few battle-brothers may be permanently seconded to the Legio by their parent Chapters, representing their parent Chapters within the Mentor Cadres. Assignment to the Legio is always an honor, never a punishment.
The Legio acts as an independent battle force, sending detachments where it will, often in aid of other Chapters or military organizations within the Imperium. Companies are composed to whatever suits the needs of the leader. Since most members of the Legio are experienced battle-brothers from their respective Chapters, the Legio can draw on a wealth of experience and training, enabling leaders to task-organize their forces and conduct operations in ways not normally available to standard battle companies.
When a battle-brother of the Legio Mentor Cadres dies, his gene-seed and wargear are maintained in stasis. They are carefully screened for purity, especially if the deceased fell while fighting the minions of the fell powers. If the gene-seed of the deceased is missing (i.e., the body is missing or the gene-seed was destroyed in combat), the Legio will procure pure gene-seed from the Adeptus Mechanicus, ensuring that it is the gene-seed of the battle-brother’s parent Chapter. These remains are then returned to the parent Chapter of the deceased, accompanied by an honor guard. The parent Chapter will receive the remains of their battle-brother, taking the gene-seed for the continued survival of the Chapter.

Battle-brothers that are temporarily seconded to the Legio will incorporate the markings of the Legio upon their armor. The most common practice is to replace the squad badge with the badge of the Legio, but the Legio doesn’t control any single method and generally leaves the decision up to the leaders of those that are seconded. Often, battle-brothers will incorporate variant badges representing the oaths they have sworn, and they may place their badges in alternate locations. The livery of the parent Chapter will otherwise remain intact. When battle-brothers return to their parent Chapter, they will often retain the markings of the Legio within their personal heraldry.
Battle-brothers that are permanently assigned to the Legio by their parent Chapters usually adopt the disctinctive livery of the Legio, replacing their original livery with the mostly black armor and red helm. The only permanent reminder of their Chapter of origin is upon their right pauldron, which is kept in their original Chapter colors.
Battle-brothers often transfer their personal battle-honors or parent Chapter traditions to their Legio armor. For example, Legio battle-brothers from the Salamanders Chapter often include hammer or flame markings upon their armor. In this way, a Legio force has a unique appearance that draws upon diverse influences.

The Legio has no specified battle-cry, allowing the battle-brothers to rally around whatever battle-cry the commanders decide upon.

The Legio shares a unique relationship with the Holy Orders of the Emperor’s Inquisition, and Legio forces often fight alongside Inquisitors. Indeed, the Captains of Legio Mentor Cadres bear the sigils of the Inquisition upon their armor. These markings, they say, indicate the Legio’s service to the Inquisition, though some speculate that the Captains themselves serve as Inquisitors, a role unheard of among the Adeptus Astartes.

Many members of the Bolter & Chainsword discussion forum create miniatures to represent their B&C personas. It is not necessary for a Legio Bolter & Chainsword battle-brother to be armed with a bolter and chainsword. Legio B&C persona can represent the entire range of standard Space Marines – scouts, squad members, chaplains, librarians, techmarines, apothecaries, etc. The upper echelons of Legio Bolter & Chainsword leadership should be considered off-limits. This includes the Captains of the Mentor Cadres (but not Captains temporarily seconded to the Legio), the Reclusiarch, Master of the Forge, Chief Apothecary, Ancient, Chief Librarian, and the Heralds. The chief Inquisitors aligned with the Legio should also be considered off-limits.
The adjustments we’ve made in updating the Legio now allow for much more variety in terms of army presentation. One player might choose an all-Mentor Cadre Legio army of black with red helmets (and varying Chapter badges), while another player might choose a Legio army that looks like, say, a White Scars army (perhaps with a few black and red Mentor Cadre Legio battle-brothers sprinkled in).
You can see a partial Insignium here.

The Legio is the mascot Chapter of the Bolter & Chainsword website. The Legio grew out of a desire to create a Chapter representative of the Bolter & Chainsword members. The main development of the Legio came after the Deathwatch Kill Team rules and background were released. At that time, the official lore mentioned that each of the main ordos of the Inquisition had a Chapter of Space Marines at their disposal. The Ordo Malleus had the Grey Knights and the Ordo Xenos had the Deathwatch. No Chapter had ever been described for the Ordo Hereticus, however, so we decided to cast the Legio in the role of Chamber Militant for the Ordo Hereticus. When Codex: Witch Hunters was released and the Sisters of Battle were cast as the Chamber Militant of the Ordo Hereticus, we were forced to do a little revision. With Codex: Inquisition, Games Workshop presented players with the mysterious Ordo Astartes. Whether or not the Legio has a relationship with that Inquisitorial ordo may never be revealed, but we’ve established the possibility of such a relationship existing.
Enjoy!
Brother Tyler

Note that this article supersedes the original Legio Bolter & Chainsword Index Astartes article found here.
Note that this is just the introductory article. The completed article will include full rules for the Legio as well as an extensive Insignium that shows battle-brothers from various Chapters of the Adeptus Astartes in the livery of the Legio, both on temporary secondment and those that have permanently joined the Mentor Cadres. Many of these battle-brothers will be from Chapters that were submitted as part of this year’s challenge. There might be some substantive changes when the completed article is published, depending upon the discussion that ensues.