Human

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.(Ctrl/Cmd+V) 

Charlie Swan

Charlie Swan is Bella Swan's father and works as a police officer in Forks. His hobbies include fishing with Harry Clearwater and Billy Black, as well as watching various sports on TV. Charlie married Bella's mother, Renée, just after they both graduated high school, and they soon had Bella. Renée divorced Charlie not long after and moved to Phoenix, Arizona with Bella. Bella later mentions that Charlie still has not quite gotten over her mother. He became accustomed to living alone, except when Bella visited him in the summer. When Bella is seventeen, she moves to Forks to live with him after her mother remarries. Initially, Charlie accepts Edward as his daughter's boyfriend, but after the events of New Moon he blames Edward for Bella's deep depression after he left her. Charlie is grateful to Jacob Black for his friendship with Bella during that difficult time, and he makes it clear that he'd rather Bella choose Jacob over Edward. At the end of Eclipse, Bella and Edward agree to tell Charlie about their engagement, and he is shown to have reluctantly agreed to the marriage at the beginning of Breaking Dawn. Charlie stays in Bella's life after her transformation; though he comes to suspect that Bella and the Cullens are not quite human, he is never informed that they are vampires though he is informed that Jacob is a werewolf. Nevertheless, he is introduced to his granddaughter, Renesmee, and is shown to be very fond of her. At the end of Breaking Dawn, he and Sue Clearwater have developed a romantic relationship.

Trivia

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.