Castellans of the Rift

Color Scheme of the Castellans of the Rift

Castellans of the Rift
Battle Cry	"Guard the gate! Hunt the hellspawn!"
Founding	Ultima Founding
Successors of	Ultramarines
Successor Chapters	None
Chapter Master	Ba'stien Grix
Primarch	Roboute Guilliman
Homeworld	Unknown
Allegiance	Imperium
Colours	Pale green with black backpack, buckle, and right poleyn with gold aquila and white faceplate with emerald green trim and helmet stripe

Castellans are a Primaris Space Marine chapter created during the Indomitus Crusade. They were instructed to clear the Nachmund Gauntlet, one of the few stable routes through the Great Rift, of daemon engines and renegade knights. Also contributed to the War of Beasts, but then again, who HASN'T?

They resemble loyalist Primaris Death Guard (puke green, skull symbols, wars of attrition... You get it), leading one to suspect Guilliman might be trolling Mortarion for starting the Plague Wars. Perhaps Cawl asked forgiveness instead of permission (ignoring Guilliman’s orders about traitor gene-seed) or Guilliman accepted the idea and was like “fuck it, let’s have some lulz.” He could use a good laugh, I’m sure.