I am a vampire in a slightly customised oWod and due to my still-strong ties to the mortal world I'm facing a slightly awkward problem. There's this human I like who recently caught the interest of some fellow creatures of the night because of his worldly power. In order to gain influence on my human they are probably going to use any means available to them.
He's wealthy, strong-willed and does not have any (known) close friends or family left. While I'm fairly sure that bribes and threats will bounce off him, at least to a degree, more supernatural influences like Presence, Dominate and blood bonds may become a problem. There are probably even more possibilities to make a human do what you want that I haven't even thought about yet. They will need him to act openly and publicly, though, so he has to retain some sort of facade to be a functioning, normal human being.
I am new to this whole undead and Camarilla game and have not accumulated any noteworthy allies yet. Among the people who are interested in my human are primogen. Blood bonding or mindcontrolling my human first is out of the question as this is exactly the fate from which I want to protect him (I also lack the powers). Additionally, he does not know what I am and what those people are and I'd prefer things to stay that way.
So, my question is two-parted:
1) How can powerful vampires try to control or manipulate a fairly high ranking public personality? What means do they have and which ones are they probably going to prefer, considering their influence should stay hidden?
2) How do I counter or prevent these means without descending into the same depths from which I want to keep my human safe?
P.S.: I am on fairly good terms with a Tremere who might know a thing or two about our kind's blood and its effect on humans. Can she help?