I started these with a black primer, followed by a base coat of GW Castellan Green. I started blocking out the base colors: VGC Dead Flesh for the face, GW Rakharth Flesh for the should pads, GW Leadbelcher for the chainmail, GW Balthasar Gold for pauldron trim and decorative pieces, GW Khorne Red for the head cowl and streamers, and GW Ushabti Bone for the random horns. This was all followed by a full strength wash of GW Agrax earthshade.
For the exposed entrails, I used GW Emperor's Children, followed with a wash of GW Drakenhoff Nightshade. Any flesh growths were painted in GW Pallid Wych Flesh, and then washed with GW Druchii Violet.
After all the washes were fully dry, I went back in and did a wetbrush on major armor plates, starting with the base colors. The fly was painted in GW Mechanicus Battle Grey, and then applied a GW Nuln Oil wash. On the plague knife, I applied a coat of a mix of GW Abbadon Black and Temple Guard blue.
For the final step in highlighting, I did a lighter wetbrush of the final highlight colors. For the dark green, GW Straken Green; the red, GW Mephiston Red; center of the pauldrons, GW pallid Wych Flesh; and the bone with Ushabti Bone. On the plague knife, I applied progressive layers of light wetbrush highlights, mixing in a bit of GW Ulthuan Grey in each successive later.
And here they are! Such pretty, gruesome, disgusting models. I love them. Their whole unclean vibe seems to fit really nicely in with the soul-less automatons of my Thousand Sons!