Yes. Yes he is pretty good.
My book club is reading Paradise Lost (we're only up to Book Two) and (as I'm sure is obvious to some) the influence on D&D is stunning. Just about everybody from the Demon and Devil entries in the Monster Manual has appeared.
Not Tiamat, of course, but I think Milton's Portess of Hell has her beat:
". . . [A]t last appear
Hell bounds high reaching to the horrid Roof,
And thrice threefold the Gates; three folds were Brass
Three Iron, three of Adamantine Rock,
Impenitrible, impal'd with circling fire,
Yet unconsum'd. Before the Gates there sat
On either side a formidable shape;
The one seem'd Woman to the waste, and fair,
But ended foul in many a scaly fould
Voluminous and vast, a Serpent arm'd
With mortal sting: about her middle round
A cry of Hell Hounds never ceasing bark'd
With wide CERBEREAN mouths full loud and rung
A hideous Peal: yet, when they list, would creep,
If aught disturb'd thir noyse, into her woomb,
And kennel there, yet there still bark'd and howl'd
Now, why don't I remember the Hell Hound bit making an appearance in D&D?
She is Sin, and the other "formidible shape" is Death. Maybe you'll get a quote about him some other time. Or you can read it yourself at literature.org.
An idea I got from a footnote in the Norton critical edition were using, about the etymology of adamant--that it literally means 'untameable'--gives me an idea about how weapons forged of this popular metal should behave. Sure, you have an Unbreakable Sword of Legend now--or, wait--does the sword have you?
Well, okay, Ego weapons already have the potential to do that. I always look for something new, but it's hard to find.