No, there are no crossover characters from other mythical stories in the Twilight series. The Twilight universe is a self-contained fictional world created by author Stephenie Meyer, and it does not feature characters from other mythical or fictional universes.
The Twilight series primarily revolves around the love story and supernatural dynamics between vampires, werewolves, and humans. The main characters, such as Edward Cullen, Bella Swan, Jacob Black, and the members of the Cullen family, are original creations specific to the Twilight universe.
While the series draws upon traditional vampire and werewolf mythology, it does not incorporate characters from other well-known mythical or fictional universes. Stephenie Meyer's storytelling focuses on the relationships, emotions, and supernatural elements within her own imaginative world.