Stephenie Meyer's Twilight series and the movie adaptations raise more questions than answers, and most of them are leveled against its protagonist Bella Swan. Her unique abilities have never been given a proper explanation, so fans have taken it upon themselves to cook their own plausible theories to figure out why Bella stands out amongst humans and vampires.
Bella Is a Succubus
Bella has often described herself as a less than average looking. As Twilight progresses, it is obvious she has no discernible qualities and lacks a magnetic personality. However, the second she steps inside Forks High School, every boy (as described by Edward in Midnight Sun) finds her attractive and is plotting ways to strike a conversation with her. Soon even Edward gets obsessed with Bella.
A fan theory suggests that Bella is unaware she is a succubus, a mythological creature who appears so beautiful to men that they can’t think of anything but her. While the theory sets aside the proper lore that a succubus preys on men by seducing them, often leading to their deaths, it explains Edward’s extreme fixation on her. Bella being a succubus also means she passed down her genes to her daughter, which explains why Jacob is so taken by Renesmee even before she was born.
Bella Is Half-Werewolf
In Twilight, vampiric powers like Edward and Aro’s mind-reading and Jane’s ability to cause intense pain with a glance do not work on Bella. However, Alice can see her future and Jasper can temper her mood.
This inconsistency is explained in a theory which states that Bella is part werewolf, as it is known that vampire powers tend to malfunction around werewolves. The theory further states that Bella having werewolf genes is what attracted Jacob to Renesmee. No werewolf has imprinted on someone with vampiric genes before, but Jacob can imprint on Renesmee because she is also part-werewolf.
Bella's Ancestors Are Vampires
Bella has been known to have a psychic shield that protects her from any mental attacks, an ability she is later able to extend to protect others when she is a vampire. A Redditor makes a detailed theory that Bella has these somewhat muted powers as a human because she is descended from vampires. The theory suggests Bella’s mother’s name, Renee, is derived from the late Roman word "Renatus." The feminine form of "Renatus" is "Renata," which is the name of one of the vampires in the Volturi Guard.
Renata is described as Aro’s personal bodyguard, as she has the power to repel physical attacks. Like Bella, she could have had the power to protect herself when she was human, and as a vampire that power is heightened. It is possible Bella’s mother is named after Renata, who is her distant ancestor, and she carried the latent ability that Bella has.
Bella Is Telepathically Connected to Edward
In New Moon, after Edward leaves Forks, she discovers she can hear his voice, giving her warnings if she puts herself in danger. While Meyers says it is their love that leads to this, many speculate Bella shares a telepathic bond with Edward.
In Chapter 11 of the book, Edward’s voice instructs Bella to let an angry Jacob calm down rather than grilling him further. In this situation, Bella is not aware that Jacob is a werewolf, so she wouldn't know how dangerous this situation actually is. However, Edward knows Jacob’s truth, so it's him warning Bella, not her subconscious.
Panic Room Is Twilight's Prequel
Panic Room stars Jodie Foster as the mother of an eleven-year-old Kristen Stewart, whose character, Sarah, is diabetic. They experience a harrowing night after they are forced to hide in the panic room when armed burglars enter their house. A Redditor believes the film’s story serves as a prequel to Twilight, as it explains many aspects of Bella.
During the ordeal, Sarah sufferers a seizure and doesn’t get her emergency glucagon injection in time. As per the theory, this delay makes her blood smell different to vampires. In that one night, Sarah is also threatened by a knife and almost dies, which is the reason for Bella’s extreme shyness around strangers.
Bella's the Reincarnation of Edward's Soulmate
In New Moon, Aro calls Bella Edward’s singer, since her blood "sings" to his vampiric senses more than it does anyone else. It is later established that vampires often come across such humans whose blood smells irresistible, but the book doesn't explain why this is.
A fan theory on Reddit suggests that any tempting humans Edward has crossed paths with in the past could have been reincarnations of his true soulmate, who he could not meet after his human life ended. While Edward manages to resist them all, after years of running away from the temptation, he finally gives in when he meets Bella.
Bella's Self Control as a Vampire Is Obvious
After Bella becomes a vampire, she astonishes everyone with the level of self-control she has. She manages to resist the temptation to kill a human and is able to feel emotions beyond her constant compulsion for blood, something unusual for newborns. While Meyer’s chalks it up to Bella being different from others, a Redditor notes that a newborn vampire’s level of self-control is dependant on how in control of their emotions they are during the transformation process.
Carlisle, Rosalie and Bella keep quiet during their transformations, silently enduring the tremendous pain and not screaming out for different reasons. It imbues Carlisle with self-discipline, allows Rosalie to resist feeding off Emmett and gives Bella instant self-control over her thirst without needing decades to adjust.