And what about very old enemies?
What did it eat down there?
A steady supply of people who ask too many questions.
Greedy and deep-digging dwarves
What were they supposed to do? Not dig? The story was rigged against dwarves from the start.
Orcs, probably
Whatever it wanted to eat.
Something that I find confusing is that if I'm interpreting the Silmarilion correctly (I'm re-reading it) Morgoth was defeated after Kazad-dûm was settled, so how did Durin's Bane even get there? Did he hide in a different cave system that just happened to be breached by the dwarves? Are we sure the dwarves weren't attacked deliberately? On close inspection, it's so weird.
Hard to say, given it's a corrupted Maiar and mostly a creature of spirit as a result.
It's kind of important to remember that the setting literally becomes "material" as the Ages progress, the world only becomes a globe after the drowning of Numenor.
Did it find a secret tunnel to a deeper cave system? Was it imprisoned after the war? Or did Eru Ilvatur somehow bring it under Moria when he was globifying the planet?
Or was it just magic, and it fled there by traveling between shadows or whatever?
On that note, there's a theory that elves can see so far because the world is still flat to them. They are mostly creatures of spirit as well, but men and dwarves are not. Who knows how a Balrog really sees the world? Was it really awoken by something as crude as a dwarf being too noisy, or was it their greed that drew its attention?
This makes me wonder... wtf was the balrog's day to day like all those years? Was he really just hibernating? I mean, the maiar get bored. I can't imagine being a shadow hellfire demon makes you suddenly never get bored.
