Kastelan Robot
Kastelan Robot are a type of robotic soldier used by the Adeptus Mechanicus. A huge, ancient robot built ten thousand years ago, the Kastelan Robot is a perfect example of the Adeptus Mechanicus’ re-purposing of technology. Nearly unstoppable, their only flaw is that of any mere machine; they will follow instructions to the letter, even if this results in their own demise. A specialist Tech-Priest - the Cybernetica Datasmith - must constantly update and reprogram the Kastelan via order dataslates, lest this enormous, clanking robot simply stride blindly into a nearby chasm.[1]
Kastelan Robots are armed to the teeth and may include two sets of arm-mounted Power Fists or Phosphor Blasters and a choice of carapace-mounted weaponry that includes yet another Phosphor Blaster or an Incendine Combustor
It is unknown what relation they have to the older Great Crusade-era but similarly named Castellan Class Robot.