"Now you know what we are, now you know what you are. You'll never grow old, Michael, and you'll never die. But you must feed!" -- David, The Lost Boys
Even vampires in search of redemption, like Barnabas Collins or Louis in Interview with the Vampire still had to find acceptable sources of vitae. In Shadow’s Kiss, you must maintain your blood to keep your vampiric powers functioning. To do this, you must either hunt, or draw blood from willing blood dolls.
Blood dolls can be recruited from willing vampire groupies (in clubs and areas controlled by vampires), or by seducing mortals and brainwashing them to the point that they serve you without question. A recruited blood doll gives you blood once a day, saving you from having to risk slayers or letting you to jump right into a quest without making a stop by the red light district.
More traditional feeding is done by hitting the streets and finding a victim that you can discreetly tap for his or her blood. The city is full of victims, but careless hunting can bring on attention from law enforcement, or worse, vampire slayers.