Board Thread:Lore Discussion/@comment-68.45.229.57-20130720115140/@comment-24327466-20131225181227

StealthBlade98 wrote: 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 with a prophecy that isn't even accurate since he knew nothing about it other than some information here and there, plus on both storylines though different leads you to stop harkon by changing the prophecy that benefits the dragonborn and Serana. It was also predestined to some extent for the bow to be found. Gelebor and Vyrthur hints at this when you meet them.

I'm not expecting my personal decisions to be canon I'm just pointing out that if you fill a game with every possibility for a character to be behave in a certain way then you can't really pigeonhole them to a contradictory role in dlc. If the bow was destined to be found killing Serana is still the smartest possible move.