The Watchguards is a Loyalist Chapter of Space Marines of unknown Founding and origin who fought to defend the Fortress World of Cadia during the climax of the 13th Black Crusade in 999.M41. Little else is currently known about them in Imperial records.
- 13th Black Crusade (999.M41) - The Watchguards deployed a full six companies of the Chapter to aid the counterattack against the Forces of Chaos from the Loyalist holdout of Kasr Trunch during the final battles of Abaddon the Despoiler's 13th Black Crusade just before the fall of Cadia.
The Watchguards' Chapter colours are currently unrecorded in Imperial records.
The Watchguards' Chapter badge is currently unrecorded in Imperial records.
- Warhammer 40,000: Rulebook (8th Edition), pg. 161