Board Thread:Lore Discussion/@comment-68.45.229.57-20130720115140/@comment-11444045-20131225045122

You being a DBH assassin in the DLC isn't really canon. You could have been a good guy with no affiliation to the DBH, Thieves Guild when you did dawnguard. The issue is Harkon's ideals is quite radical and both storylines, though different leads you to stop harkon by changing the prophecy that benefits the dragonborn and Serana.