At this point, Trevorcard might just be the case. But what's more important is who/what gave him this power? Dracula couldn't have done it since he believes he killed him and turning someone who had already nearly killed you in battle as a human into a more powerful being and not expecting him to use it against you seems idiotic.
Dracula:"Hey you almost killed me, im gonna turn you into a vampire and give you a very significant power boost."
Servant: "Master, I don't think it's a good idea to turn someone who nearly defeated you into a vampire, wouldn't that make him stronger and a bigger threat?
Dracula: "I always wanted a son who was just like me, now he can see the world as I now see it. Besides im only giving him half of my power so he won't be as strong as I am, what could possibly go wrong?"
*wakes up in a coffin 1000 years later*
Dracula: "Yeah maybe that was a bad Idea."