One might think, considering the Name of the Game, that the Description means that you have to win a BR Match, however, this is not true.
The Game has a "Masquerade" Mechanic, basically, youre considered a normal Human, aslong as you keep your Masquerade up. When you do something suspicious such as diablerizing other Players, or sucking the Blood of Civillians for Perk Upgrades, while being seen by NPC's, you will break your "Masquerade" and get tagged for the whole Lobby for a certain Timeframe. This is the Bloodhunt, and upon surviving it, you will gain this Achievement.