The most mysterious of the Emperor’s servants, the Grey Knights are a unique Chapter of Space Marines. Each is an elite warrior-mystic clad in sigil-scribed power armour and wielding archaic weapons through which they channel their otherworldly abilities. They are a purified order, incorruptible and possessed of iron fortitude. They have to be, for the Grey Knights face down the most nightmarish horrors from the seething depths of the warp: the Daemons of Chaos. Their Brotherhoods use the shifting immaterium to their advantage, drawing on it to direct coruscating energies and outmanoeuvring their foes through pinpoint teleportation. Their warriors unleash a storm of firepower, supported by sanctified battle tanks, gunships, and giant warsuits whose psychic weapons can banish the greatest of Daemons back into the warp. Inside this 112-page book, you'll find: - The clandestine legacy of the Grey Knights, including their myth-shrouded founding and classified operations throughout the history of the Imperium - A guide to the unorthodox organisation and heraldry of the Grey Knights and their various Brotherhoods - A Grey Knights bestiary with background details for every unit and Character featured - A showcase of stunningly painted Citadel miniatures - Rules for units that are available to the armies of the Grey Knights – including 32 datasheets - Stratagems, Relics, and optional secondary objectives that illustrate the mystifying goals and remarkable tactics of the Grey Knights - A Crusade section providing Agendas, Crusade Relics, Battle Traits, Requisitions, Psychic Fortitudes, Honoured Titles, and unique Daemonic Nemesis rules You will need a copy of the Warhammer 40,000 rulebook to use the rules included in this codex.