A 'zombie' super robot on a dead world.
The size of a typical mechanoid, it cubic out plating is a light grey and dark grey mix. It's humanlike metal face, is decomposing, creating 'facial' hair and wrinkles.
The Mech, is a techno plague infected corpse of a super robot. It's plasma hearts and the Embers it held, are now long gone, replaced by a makeshift Bio-Core, composed of viral matter. This weak replacement, means that much of their mass is 'dead matter' and can easily fall off.
The mech was one of several soldiers who fought against abominations. Like the others of its battalion it fell in battle on the planet Cassus. Their bodies never recovered.
A trace amount of their enemy remained however, they were infected with the Techno Plague, thus it and others became, biomechanical zombies after death, waiting for a stimulus to move.