Re: Where the Watcher came from ?:
I heard a theory that would put Turbine in some hot water. It is that the watcher served as the dwarves guard for moria and that it served them. Now some of you may ask why it attacked people:
Balin's expedition: balin was not ancestral king, so wasn't recognized by it.
Frodo had the ring which was evil, so watcher thought that frodo was evil.
These reasons would make fighting it pointless since it is a guardian
"It's a dangerous business, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to."