Avoid Blood Omen 2. I had bought it a few years back and on top of the story making no sense with regards to the series continuity, it was the glitchiest game I've ever played. About ten or fifteen hours in I couldn't even progress because a problem with the game kept me from loading my file. I promptly returned it and got a better game. Maybe the story would have made more sense if I had been able to complete the game, but since it seems to have no bearing on any of the events in Defiance, I doubt it's anything more than a throwaway story. Defiance would be the game you want. It continues the story directly from SR2, was a much more enjoyable experience than Blood Omen 2, and does a lot to answer some of the questions left unanswered after SR2.