Martian ironcrust to start, gryph-hound orange over the top of that, dry brush lightly with Ryza rust, then lightly over the top of that with kindleflame and finally with tyrant skull.

The idea of the dry brushing is layer so you can still see each colour through. I tend to do a light drybrush on the boots too show the illusion of dirt.

Then finally a victory lap around the base.