As long as you don't feed you will not gain any vampire powers and you will not have any vampire weaknesses I've been playing it for a couple weeks as a hybrid and was able to achieve this as long as I didn't feed. I am feeding and every combination you can think of as a vampire lord, in werewolf form, when I'm using melee attacks, or even if I'm across the room. The screen just automatically goes blood red at random points and says your vampire powers are suppressed as you feed. I tested to see if it was really affecting me and sure enough my weakness to the Sun grew over a period of time as if I really have fed. I'm playing on xbox 360.