The Kastelan Robot is reasonably common in the Mechanicus forces of Mars and served with the Emperor's forces in the Great Crusade and with many sides during the Unification Wars on Terra. They have been around for well over 10,000 years, some say 20 or even 30,000 years, making them likely to be amongst the far-flung worlds who lost contact with Terra tens of thousands of years ago. This is how this particular machine is found in the forces of the Heirophant.
The head started as the backpack from the Thundrik's Profiteers with added Skitarii and Kharadron bitz. This wasn't meant to look like the torture droid from the Death Star in Star Wars, but maybe it's so ingrained in my consciousness it just came out! The torso was an interesting challenge as it's quite large and bulbous, and very Adeptus Mechanicus looking. In fact the front of the torso actually has the control surface from the Adeptus Mechanicus Tech-Priest on it (alluding to the idea that you don't actually need a Tech-Priest to run it at all) with a Skitarii backpack and the front of a Kharardon helmet, echoing back to the first Heirophant troops I did. The back of the torso was quite a bit of fiddly work, removing almost all trace of the original power pack and adding various Kharadron backpack, tubes and pipes pieces. I'm very happy with this part actually, and may revisit the paint job later on.
The arms are pretty stock standard, but cut off at the elbows and new elbow joints added from cut up sprue to give added movement to the pose. The weapons needed to be something totally different from the Imperium but also work in with the look i'd already started - so I cut down the front gun from the Arkanaut Ironclad, added some pipes and a cut-down sensor from the a Skitarii backpack as well as another form the top of a Skitarii gun. The second weapon is my favourite and based on a Gundam Acguy missile pod arm. It's actually two re-purposed parts off the Arkanaut Ironclad engine with holes drilled into it to make the launch tubes. The magazine underneath is a Cadian grenade launcher cut up and re-positioned. The legs are pretty standard, just using the groin armour from a Space Marine Centurion cut down to fit. The bottom of the legs were then given stretched sprue around the front armour plates to be echo the MKIII armour used on the legs of the infantry. The toes also got some love, with trigger guards from Skitarii guns used to create these upturned toe decorations, sort of Byzantine looking - an echo back to another Empire from the past.