Cleon
Legend
I don't like the idea of DR depending on the type of critter that attacks it. Just seems weird (and contrary to the spirit of DR). We could go DR 5/- if you prefer.
Yes, I'm not that keen on the idea of type-specific DC either. We could give it some kind of "Parry Dragon" special ability, but I think it's got more than enough special abilities as it is!
DR 5 should be enough.
Do you agree to Unholy Toughness?
That's one it definitely needs. Indeed, most Undead should get it as standard!