Boris

He is the vampire that changed Dean into one. Which makes his blood the only one that can cure Dean.

Background
He saw Dean in the alley way attacking one of his men. So he jumped in and attack Dean, but because was so nice looking, Boris decided it would be a waste. So he turned Dean into a vampire. Later, Boris sees Dean again, and treats Dean like a friend. He tells Dean, that they are both recruiters now. He shows Dean how they draw people in using Poetry, to attract vampire fans. Once they bring the fans in, they are converted and used to recruit more people. Boris also reveals that he is 600 years old.

Boris tells Dean is wasn't his idea, but his "father's" and promises to give Dean a private tour later. As they are walking, Boris hears Dean pull a syringe out and stops Dean before it can touch him. As he is retraining Dean, a high pitched noise breaks out and Boris collapses. As Dean is hacking through the vampires, Boris tells him its too late and attacks. Dean wins and is found standing over Boris's decapitated body. Once they have Boris's blood, they cure Dean.