Forget about the need to add a variety of color, the second post (before the redo) is fantastic !! Plus I think the stark-looking trees in the background really add to the grim combative mood of the picture. Love that unique perspective, makes you feel like you're right inside the battle.
My critical/negative side says I would like to see the lighter-half of the creature's cheekskin match it's armskin tone a bit more, only because the roughness of his cheek almost dupes me into thinking I'm getting a transparent view of the trees behind it's head.
Nice pics overall.
I'd really like to see more of your work with the same artistry as that second post in particular.