"Congratulations, you're hired!" Is usually something everyone is happy to hear. Except, the job... You're the local vampire lord's publicist. Well, congratulations.
Your job is quite literally to give a villain undeserved good publicity. Failure? No problem, if you want your new boss to kill you, your friends, family, and that guy you buy those yummy croissants from at the market. And not just any death, no... we're talking about someone that enjoys inflicting suffering on his 'meals', before drinking them dry.
There's an upside, though! Your boss likes keeping his... meals and lifestyle as low key as is possible, provided it makes keeping the sheeple tame and compliant. And you can even request a budget to make your job easier(ish).
There are three target audiences you need to deal with: high class, mid class, and low class. Simple enough. Doubly so, given all the inter-class fighting.
High class 'nobles' like being on top, so they're likely to keep the mid class beneath them by any means necessary.
Mid class 'citizens' want the high life, and will do anything to get it.
Low class... well, they're just trying to survive. They're usually too tired from working 12-14 hours a day just to be broke, so there's little risk of them caring so long as they and their family/friends aren't directly affected.
As well, slavery is a thing. So it'll make 'arranging meals' far simpler. Even though... it also doesn't. Your boss has a bad habit of killing the 'blood bag', and he needs to have fresh blood (fresh from the vein, naturally) every three days, at most. This isn't too bad given the population density (the city has in excess of 200 million registered (non-slave) citizens.
So. How are you going to keep your employer alive so you'll get paid?
Things to keep in mind: (this is a late edit, so I'm not going to hold this against already offered answers)
- Vampires need to eat regular food, to have calories to burn.
- Your boss has no real preference for blood bags, and he has AB-positive blood, so the bloodtype of the blood bags is not relevant.
- You cannot choose your boss's meals, and 'helpfully suggesting' might upset him. (read: make him want to kill you on principle alone)
- You have contacts with local writers, so influencing what is being written (newspapers and the like) is plausible, but difficult.
- Getting your employer involved will create the exact problems you are trying to avoid. (Though he is more than willing to feed on the 'haters', it's the kind of publicity you want to avoid.)
- People already know about vampires in general, but no one has had any substantial interaction with them. However, the general consensus is that vampires are evil and vindictive (which you confirm with one meeting with your boss).
- People go missing all the time, and there are thousands of homeless people. So a few hundred going missing per year won't even be noticed.