I was thinking that my character would be a betrayer to both sides of the conflict- in other words, seen as less than dirt by everybody.

Would it be possible to be a spirit summoned centuries/millennia ago (whichever is canonically appropriate)? I was thinking along the lines of a protective spirit summoned to protect a church, but when it got raided (probably by the forces of either Pritharin or Ganaron) it ran away. This would lead it to be reviled as a coward and a traitor by both sides.