Digital Devil Saga

Another commission, this one based off of a DDS game, which I've never heard of before. They didn't request any animation in this one, but when I realized the characters can morph, I thought that would be a cool way to make a signature for the set.
Here is the set, along with their request:

1) What theme - Digital Devil Saga, preferably Gale or Serph based (maybe both) (Message me if you need information?)
2) Color scheme, if you have one in mind - I'd like grays, and perhaps some light blues/greens.
3) Images you would like me to imitate, use, etc, or anything you have as an example of what you'd like done - Sadly, none. I'd like one similar to the Med, Rave, or first one. Not big and blocky, but a slimmer bar with images. maybe not even a bar at all? I 'unno. Go crazy.
4) Any words you would like included - Rend, Slaughter, Devour your enemies.
5) Anything specific; for example if you hate the color pink, want no words at all, don't like a grunge look. - Not really. Uh.. I'd like a sort of grungy look. Like, sort of Post-Apocolyptic, you could say. Mechancial and dirty?