Besides being two of the biggest film and book series of the modern era, Twilight and Harry Potter may share a common thread. Though the content of both series vastly differs, they are both excellent fantasy stories that happen to feature some sort of werewolf. In the Twilight films, Jacob Black is a member of the native Quileute tribe and inherits the ability to shapeshift into a wolf at his will. Similarly, Sirius Black from the Harry Potter films is an Animagus that turns into a large black dog, often mistaken for a wolf. Therefore, it’s unsurprising that there’s a fan theory that suggests that Jacob Black and Sirius Black could be brothers.
In his fifth year at Hogwarts, Sirius gained the abilities of an Animagus — a witch or wizard capable of turning into a chosen animal at will. He chose a giant, black dog as his animal, which came in useful during his time trying to evade capture by the Ministry of Magic. And never registered with the Ministry as an Animagus, which made him seem more like a threat.
On the flip side, Jacob Black gained the ability to turn into a giant wolf in his teenage years. Unfortunately, he didn’t get a choice — due to his Quileute heritage, the ability was ingrained in his DNA and was just waiting for some local vampires to activate it. Though Jacob initially was very angry about his newfound identity, he eventually warmed up to it and started to become more comfortable as a half-wolf.
Now, with their backgrounds presented, the theory that these two iconic characters could be brothers isn’t entirely unfounded. Besides their names, they both have the ability to choose when they turn into their canine counterparts. Unlike the typical werewolf stereotype, which has no choice under a full moon but to turn into a monster, both Jacob and Sirius choose when they want to change. And by using that logic, the only true werewolf in either series is Remus Lupin, one of Sirius’ closest friends.
Without concrete evidence to put to bed the idea that these characters share some kind of background, it’s hard to ignore. Both Harry Potter and Twilight feature rich, fantasy-laden worlds, so who’s to say that, through some strange family tree, Jacob and Sirius couldn’t find themselves interacting at a family reunion.