On Saturn's moon of Titan, a massive basalt fortress- monastery tears from the ice above the oceans of liquid methane like a jagged, black spire. The monastery is home to the most secret of Chapters in the Imperium, the Chamber Militant of the Ordo Malleus, the Grey Knights. The dusty, echoing halls of this fortress are hung with battle honours stretching back almost ten thousand years, though none outside the Grey Knights or Ordo Malleus would recognise the names of the conflicts inscribed in the faded gold lettering.
Legend tells that it was around the time of the Second Founding that the Emperor ordered the creation of this secret Chapter of Space Marines. The fragile Imperium had only just survived the galactic civil war of the Horus Heresy, and was still very much at the mercy of the powers of Chaos. The Emperor understood that it would require a dedicated band of incorruptible warriors to protect it from the dread creatures of Chaos in the days to come, and so the creation of the Grey Knights was undertaken in great secrecy. Where other Space Marine Chapters were created from the gene-seed of existing Chapters, the Grey Knights were unique in that their gene-seed was said by some to have come from the Emperor's own flesh. The Ordo Malleus was in its infancy at this time, the corruption of Horus lending new impetus to the creation of an order tasked with the hunting and elimination of the daemonic.
The Grey Knights were permanently attached to the Ordo Malleus, becoming the hammer with which these servants of the Emperor would smite the forces of Chaos, and one of its Grand Masters is traditionally a member of the Inner Conclave of the Inquisition. Space Marine recruits are often drawn from feral words and the Grey Knights are no exception; its recruits are emergent psykers plucked from the most savage warrior cultures imaginable, where only the bravest and strongest survive. Recruits selected to join the Chapter are returned to Titan to begin the long and arduous process which weeds out those without the physical strength and immense mental fortitude to become a Grey Knight. Only the best of the potential recruits survive this selection procedure and are deemed worthy to begin the process of transformation from human to Space Marine. Once their bodies are implanted with the precious gene-seed, the aspirants’ true training can begin.