Immortal, I'll assume for the moment you don't want to start a faction opposed to the vampires, so I'll leave that alone for now. However, seeing as you are going for the classical, gothic nobility feel, is it possible that the vampire nobles would have mortal knights in their employ? Knights which might not be aware of the vampiric nature of their employers?
If so, I would be interested, as I'm not overly fond of roleplaying a vampire myself. Of course, if you're keen on the idea of a group of mortals opposing the vampires altogether (as suggested by Woolymamoth45) I'd be up for that too. Just scoping out the different options.
Thanks.
Or if you are interested you could be one of the mortal apprentices to the magicians in my family.
I had an idea recently. After training their apprentices for a time, they decide it is time to test their skills, and so go down with their apprentice into the sewers, and work with the apprentice to slay one of those apostates, the insane vampires who could not adjust. This would gain the trust of the apprentice and his family, give the apprentice some experience, remove the insane vampires from the noble vamp's worries, and improve their reputation and hide their condition (hard to be called a vampire when you kill them).