The Grey Knights are a secret order of Space Marines made up of psykers who are dedicated to combating threats of the warp. They operate as the military arm of the Inquisition’s Ordo Malleus. The Inquisition for those of you who are new to the Warhammer 40K universe, are a powerful organisation within the Imperium of Man tasked with eliminating threats and Inquisition are much like a secret police in modern day terms.
The chapter is headquartered on Titan; which is one of the moons of the planet Saturn. Interestingly enough; they do not adhere to the Codex Astartes and are not organised like other Space Marine chapters. Lore-wise this makes them quite interesting as they themselves could be a threat to the Imperium should the Inquisition choose to take power.
In-line with their secretive nature, the existence of the Grey Knights is shrouded in mystery and only Chapter Masters are aware of them. In the books, other Space Marines treat them with some suspicion and the Grey Knights largely keep to themselves; choosing not to fraternise with their brother Marines.
Why I think the Grey Knights are cool:
- The chapter was formed in secret towards the start of the Horus Heresy by Malcador the Sigilite with the creation of the Knights Errant
- Nathaniel Garro; one of my favourite characters from the books is a founding member of the Knights Errant
- Their gene-seed originates from the Emperor of Man himself
- During their founding, Titan was sent into the Warp by Malcador towards the close of the Horus Heresy; emerging a few years later with a fully developed Space Marine chapter due to the altered flow of time within the Warp
- Colour scheme wise; their power armour is largely made up of silver, gold and reds which makes them like very knight-like