It is unknown how exactly the brides are related to Dracula, whether they are actually his wives or perhaps his sisters or even daughters. As they tell Jonathan Harker, the Count does not actually love them and they are merely his servants.
Beneath the brides' charming exteriors are ferocious, savage predators. They possess strength and power similar to Dracula's, though to a lesser extent. Though devoted to the Count, their violent urges could get the better of them, as demonstrated when they disobeyed Dracula by attempting to feed on Harker.
Like their master, the brides are repulsed by religious objects and garlic. They also cannot tolerate sunlight or the touch of silver.