These Plague Marines have a techno-virus/cyberpunk vibe.
  - Prime with   Necrotic Flesh  because you didn't think ahead.
- Paint all the armor areas with   Deepkin Flesh  
- Paint the horns with   Abaddon Black  
- Paint the Tentacles and tongues with   Calgar Blue 
- Paint Trim and emblems with   Gryph-hound Orange 
- Think about what to do next...