The Knight Castellan, along with the Knight Crusader is one of the heaviest types of Imperial Knight-armour patterns made by the Adeptus Mechanicus Forge Worlds. Although slower than the other Knights, this pattern benefits from substantially increased firepower and much thicker armour. Because of its great bulk, the Castellan cannot move fast enough to generate the charge needed to operate a Shock Lance. Instead they are used in a fire support role, providing heavy weapon cover for other Knight units to charge in, and picking off threats to the main force from the rear. The trademark feature of this pattern of Knight is the huge shoulder-mounted Quake Cannon, a modified Titan weapon that can destroy Titans and buildings alike. The Knight Castellan supplements its weaponry with a multi-barrelled Autocannon. Although relatively short-ranged, the hail of shells it delivers can easily cut a swathe through most enemy infantry and light vehicle units, or strip a Titan of its Void Shields in an instant.
The original incarnation of the Knight Castellan was provided in the supplement found in Titan Legions (2nd Edition). This account of the Knight Baron's history has largely been superseded by newer canon in accordance to Codex: Imperial Knights (7th Edition). Please note, that this version contains old background information that is no longer considered canon according to the current iteration of the Warhammer 40K universe.
- Titan Legions (2nd Edition), pg. 30
- White Dwarf Magazine #181 (UK), " 'Eavy Metal - Imperial Knights," pg. 42