Middle Earth Riddles: The Terror Continues

[Nuranar]

There are two of them, they are brothers
The second twice as large as the first
To know the second, you must meet the first
Although only the second is ever sought.
Every man meets them.

Who/what are they?

Boy, Kalimac, this is hard! Question: Is the second actually twice as large, or is it just larger in a metaphorical sense, and not necessarily twice as large?

Hmm...Guess I'll keep working on it!