Ronak looks like a mash up of Predator, that Thanator creature from avatar, and something much more prehistoric. I'm debating between earth-tone red/brown and a bit of green for the top, possibly a brighter underside, or going with something brighter since it probably isn't necessary for it to have camouflage. I'll have to wait and see when it's here.
I am not sure if he is pure evil or a creation of the earth. If he is evil I will color some blue in the cracks to make him look filled with power. I was thinking using some green basing and maybe some tiny plants (usually for basing of figures) to stick on him here and there to make him look like he raised from the earth. I would hate to just paint him brown and shade.
Here are some of my Blood Rage figures. I imagine a tan shade ("Bone" maybe) and then shade down. Fill in cracks with blue for "power" and then a bit of "flocking" from my base supplies.