I'm a fan of one, myself, but in the end, the choice is always the creator's. That's you.
Stages is cool, but necessary? Hmm... I think uniformity would serve The Shadow's purposes best but, then again, you decide. For those who read the Eragon saga, that idea worked out pretty well for the Ra'zac/Lethrblaka. But are they simple corrupted and broken creatures that The Shadow has transformed or manipulated for his own ends? What, exactly, are they and how to they aid their master? Is it possible for them to think for themselves or are they totally dependent upon him?