The Castellans of the Rift is a Loyalist Space Marine Chapter comprised entirely of Primaris Space Marines created from the lineage of the Ultramarines and raised during the Ultima Founding of ca. 999.M41.
It is the unenviable duty of the Castellans of the Rift, given to them by Roboute Guilliman himself, to maintain and defend the Nachmund Gauntlet, that stable channel through the roiling tides of the Great Rift that empties into the Vigilus System.
They have engaged in numerous raids upon the Fallen Knight World of Dharrovar, and have fought at both the Imperium Nihilus and Imperium Sanctus ends of the gauntlet to drive back Renegades, Traitors and xenos raiders alike, at great personal cost.
- War of Beasts (Unknown Date.M42) - Since Primarch Roboute Guilliman despatched the Castellans of the Rift to the Nachmund Gauntlet, they have been locked in a struggle to drive back the hordes of daemonic war machines and Renegade Knights blighting that channel of space. When war broke out on the vitally important Imperial world of Vigilus, the greater part of the Chapter was engaged in warfare against the Heretic forces that had revealed themselves on the Knight World of Dharrovar. Still, two companies joined the war on Sangua Terra and a further two travelled to Vigilus. With experience fighting against the machinations of Chaos, in the third stage of the War of Beasts they hunted the dark cults of Storvhal with commendable efficiency and resolve.
Chapter markings and unit designations are white. The white squad specialty symbol -- battleline, close support, fire support, Veteran or command -- is displayed on the right shoulder pauldron, while the left pauldron proudly displays the Chapter's iconography.
The company number is displayed as a High Gothic numeral on the right knee plate on a field of black. These numerals reflect the Chapter's Ultramarines heritage.
The black High Gothic numeral displayed in the centre of the squad specialty symbol on the right pauldron designates squad number.
Battle-Brothers display pale green helms with a vertical dark green stripe down the centre. Sergeants wear red helms.
Lieutenants wear pale green helms bisected by a large red stripe with a pair of smaller white stripes painted to either side.
The faceplate of the helms is painted white rather than green, mirroring the skull that is part of the Chapter badge.
The Castellans of the Rift's Chapter badge is a white skull placed over a pair of crossed chains.
The chains represent a symbolic barrier against the evil that these Astartes fight.
- Codex Supplement: Ultramarines (8th Edition), pg. 25
- Imperium Nihilus: Vigilus Defiant (8th Edition), pp. 75, 79, 86
- White Dwarf 5 (October 2017), "Eavy Metal - Create your own Chapter," pg. 118