I am pretty sure I will look over it in 2 days again and maybe bring in some more details in the focus on the head and belly, but in the overall I like this sketchy look. When I go for a worked out detail look, it usually becomes too ... clean.
Do you play World of Warcraft? What you described is almost identical to Erudax (Grim Batol Heroic End Boss): You should watch this, it might get you some more ideas. It's interesting because this boss combines some form of shadow power with those hatchlings that spawn from the eggs in the cave unless you kill the minions: http://www.youtube.com/watch?v=dPwO0vkPt5E
I think the idea of adds hatching is very good, and believable. I just keep mentioning WoW here because RiFT is supposed to be a rival, and I do not know how much similarity the colossus contest likes to see, whether it is intentional or not.
Thanks for the hint. I played WoW until Icecrown was finnished.
The boss in the video has a little bit of what I described, but not so much. He loks different and he doesnt really hatch something himself either. And the adds just walk in the room. So I dont think thiss will be a problem.