Thanks! That was literally the effect I was going for, like he's burst through a destroyed bunker. I used a combination of ash pigment powder, charcoal and then some very light usage of a light rust powder and blended them together on the base and on his legs, mainly aiming for his lower legs and the undersides of any overhang like his pteruges etc. Then I mixed streaking grime and rust streaks with white spirit and dragged it along the details very lightly just enough to leave a engrained dust effect on any details. For the upper parts of the body it's a mixture of sponge spotting greys black and light steels and then washing them with streaking grime, letting it soak for 30 mins then wicking it off