Humans are the basic species in the Twilight series, from which vampires, shape-shifters, and werewolves originate. Lacking vampiric enhancements, they are considered prey by most vampires, who need their blood for sustenance.
Human beings who discover the existence of vampires are considered a threat, and a Volturi-enforced law has been implemented dictating that said humans either be killed or changed into vampires, causing Jane, Alec, Demetri and Felix to be sent to Forks in Eclipse. It is also illegal to create immortal children, that is to turn human children into vampires, because they always lack concentration and self-control, and are therefore un-trainable and dangerous.
A human who is to be changed into a vampire needs just to be bitten once, to allow venom to enter their bloodstream. If blood is consumed by the vampire during this time, it is highly unlikely that he will resist the temptation to kill the human before completion of the transformation. The pain accompanying the transformation is described as the worst possible by all those transformed into vampires, and in Breaking Dawn, it is described as a burning feeling by Bella. A human, however, can also be changed into a werewolf by being bitten by one, and it remains unknown whether the conversion is painless.
La tua Cantante
La tua cantante is the Italian expression for a human whose blood particularly appeals to a certain vampire in an extreme sense. In English, it means "your singer", but is usually shortened to "singer" whenever someone refers to her/him.
The smell of each human is different, and certain humans smell more appetizing than is usual to vampires. The more appealing any human's scent and taste is to a vampire, the more difficult it will be for that vampire to leave the human alive.
Infrequently, a specific human will smell nearly irresistible to a specific vampire. "Singers" are individual phenomena; a person whose blood sings for one specific vampire will not have the same effect on all vampires, though they may still find the human mouthwatering (As Laurent said to Bella when she was in the meadow that she and Edward used to hang out before he left Forks). While there are some humans whose scents are more appealing to vampires in general, that appeal does not reach the level of a singer.
Singers are considered by most vampires to be a great find, the drinking of whose blood is an experience to be savored.
- Bella was Edward's singer prior to her becoming a vampire. He was so appealed by her scent that he found his throat burning, and barely retained enough self-control keep from killing her. Eventually, his restraint developed to the point where her blood no longer bothered him. The blood of singers is described by Edward as being said vampire's "own personal brand of heroin".
- Emmett had stumbled upon two, one tasted better than the other. Neither was left alive because he lost control the moment he smelled their blood.
- Alice was James's singer before she was turned into a vampire. When Alice was turned, James was furious that he never had a chance to taste her blood and killed her creator.
- Nahuel's mother, Pire, was Joham's singer, though not quite as potent as Bella was to Edward, and he maintained enough control to impregnate her.
- Aro was the first to use the term, and it was the first time any of the Cullens, besides Edward, had heard the term.
According to Aro, the human race has weapons that could destroy vampires, but little chance to use them, given the latters' strength and speed, and the fact that their existence is considered mythical. The situation, however, worries him.