[JohnBooty]

    I thought that his appearance in the book was just 
    a contrivance to introduce the sense that this 
    was all middle earth, successor to an older earth 
    older than the "old" things of Middle Earth

Yes. On a nuts and bolts level, he has a single purpose: so that the reader knows there are things older than elves; things that elves (and maybe even wizards) don't know about.

I see why many people hate Tom, particularly many engineer-types who want their fantasy worlds to be meticulously detailed and explained.

And from a traditional storytelling standpoint, he's a total dead-end with zero effect on anything else in the story.

Yet, I love him. It added to the sense of wonder and mystery in the world. Even Elrond doesn't know about this guy? Bonkers.

[thehappypm]

He is the reason why they can kill the witch king