I was providing two seperate options, but there's not much I could do to really make the idea clearer there.
Instead, here's a couple mockups:
A more classic "godzilla" type of dragon look. Built for defense and intimidation
A more twisty "lizard" looking dragon, built for climbing around on walls and being a nuisance
And a more out-there "chimera" style dragon, vaguely inspired by armadillos for the back half. Probably some sort of horrible dark souls mutant. Built for a more monstrous fighting experience, probably has some weird and unexpected attacks.
Think about what you want the fight with this thing to be and work from there, that's usually been a good technique for me.