Oblivion question

Hello all,
This post isn't actually about the book listed above, it is a question to all readers who may know of a book I had read but cannot remember much about.

I don't remember any key details of the book, so I will try my best to recall anything I can remember.

The book was paperback, with a medium blue cover. I do not remember there being much (if anything) in the way of cover art. There seemed to be around 300 pages or so. It may have been published in the 1999-2004 year range, but I am very unsure about that.

Things I am sure of:
-The protagonist was male.
-This book was part of a series. (Maybe 3 in total).
-The book was about a man who had not seen violence because it had not happened for many years.

Things I am less sure of:
-I believe the time was set in the future.
-The plot was loosely based around this protagonist who had never been violent (nor encountered fear?) and an unknown being threatened their world. The man somehow came upon this being, but I do not remember what it looked like.
-I believe there may have been the world Oblivion, or Obsidian, in the title or subtitle.

I am scouring the fantasy, low-fantasy, and heroic fantasy popular book pages, and have yet to find this book.

If anyone knows any information about this book, I would really appreciate any knowledge you can pass along.

Thank you.