"...we...surrender...By the mercy of the God-Emperor...the war is over...we have surrendered ..."
— Final Vox-intercept, Void Colony Sigard VII
The Carcharodons are a Loyalist Space Marines Chapter of unknown Founding whose gene-seed may have originally been drawn from Raven Guard stock who participated in the latter stages of the Badab War. They were a fleet-based Chapter until in recompense for their role in the Badab War they were given control over the Mantis Warriors Chapter's territory in the Maelstrom Zone of the Ultima Segmentum, a group of Feral and Feudal Worlds called the Endymion Cluster. The Carcharodons may actually be the same Chapter as the Space Sharks; the term Carcharodons may simply be an alternate name for that unit of Astartes.
Tactically, during the Badab War, the Carcharodons operated almost exclusively as a rapid-strike force, disdaining any kind of protracted engagement whenever possible, preferring to approach their targets either with extreme speed or by stealth, which allowed them to strike with the element of surprise on their side whenever possible. In combat they endeavoured to close ground with their enemies swiftly and do battle either in hand-to-hand combat or unleash their ranged firepower at near point-blank range. For this reason each Carcharodons Space Marine, regardless of whether they were part of the Chapter's Devastator Squads or its dedicated Assault Marines units, was observed to carry a plethora of bayonets, blades and chain weapons in addition to their normal armaments so that they were always able to engage in vicious and bloody melee combat.
The Carcharodons conform roughly to the tactical and squad doctrines laid down in the Codex Astartes, but demonstrate considerable deviation from its approved command structure and company arrangements. In some instances it appears that the Chapter has abandoned wholesale the approved symbology and insignia of the Codex in favour of personal and often highly totemic markings. Only a few intelligible accounts of the Carcharodons exist that tell of the Chapter's very disciplined order of deployment and combat, despite the evidence from casual observers that they are a barbarous and savage Chapter in nature. Their tactical deployments and use of shock-assault tactics is highly reminiscent of the Black Templars. Although these Chapters are diametrically opposed in character, they both tend to display an overriding desire to close with the enemy and shatter their foes in bloody personal combat.
Each company of the Carcharodons operates similar to a Codex battle company, but is augmented with an attached auxiliary force of Scout Marines and spearheaded by dedicated Terminator Veterans who serve as personal bodyguards to the company's commanding Captain. There appears to be no reserve companies in the Carcharodon order of battle, but it is suspected that not all of the Carcharodon's companies conform to the same pattern of organisation.
The Chapter also includes both Chaplains and Librarians, although the forces observed in action during the Badab War seemed lower than recommended by the Codex in the number of Apothecaries and Techmarines in their ranks. These last two cadres may have been held in reserve in the Chapter's fleet, a not uncommon practice for fleet-based Chapters who spend large periods in isolation. This structure puts the effective strength of each company at around 100 to 120 Initiates and 20-30 Neophyte Scouts, although the exact size and disposition of the Carcharodons Chapter as a whole remains unknown.
During the Badab War the Charcarodons Chapter demonstrated a number of highly distinctive traits and trappings that set them apart from their brethren fighting on both sides of that conflict. Their equipment was observed to be of ancient provenance. Much of their arms, vehicles, wargear and other equipment were of designs and patterns that covered the span of the Imperium's breadth and history. Examples include such ancient weapons as the Phobos R/017 Bolter and the widespread use of Mark V "Heresy" pattern Power Armour by the Chapter's Battle-Brothers. The Chapter also seemed to possess an unusual contingent of Terminator Armour suits, of which many appeared to be heavily modified or augmented in unorthodox ways to keep them combat worthy.
In physical appearance the Astartes of the Carcharodons possess a greyish-pale pallor to their skin, with their more venerable members possessing liquid-like black eyes without a visible iris or sclera, much like the ancient Terran sharks for which the Chapter is named. Aside from these physical marks, there is no common type of physiognomy or genotype among them, pointing to the reality that Carcharodon Neophytes are taken from many different worlds across the galaxy rather than from a single source of new recruits like most Astartes Chapters. Gene-seed samples taken from the Chapter and tested for purity by the Adeptus Mechanicus have proven to be untainted although subject to some long-term degradation, and possessed of several markers found in the uncommon Raven Guard bloodline, a mutation of which may have resulted in their unusual physical appearance and is the basis of some of these Astartes' unusual phenotypical traits.