It is my view that you are interpreting things a bit too personally. They are vampires. Rob, as a human would never be able to beat them unless they let him. The taunting is also a training tactic, to make him focus or be punished.
That they have fun with it is obvious, but, you attribute to malice, what is only (for them) a bit of a workout with what amounts to little more than a child, both in age and in power.
While I can understand, that attribution to malice, smells a little of lack of confidence. Maybe not, but...
Try, if you want, to re-frame their intentions, removing any ill intention, that it is only imagined, I assure you, and enjoy the sparring with 2 very competent, powerful and experienced fighters.
Peace