They could go on a road trip together. Along the way, they might encounter strange creatures or visit mysterious places. Maybe they find an old, abandoned mansion that holds a key to their family's past.
Perhaps they could be part of a detective - like adventure in their hometown. As cousins, they have an inside knowledge of each other's quirks and strengths. Bella could be good at noticing small details, while Elena is great at talking to people. Together, they could solve a mystery that has been plaguing their community.
In fanfiction, Bella and Elena being cousins can open up various storylines. Maybe they could have a shared family secret. For example, they might discover they are part of a long - lost magical family line. Their relationship could be full of sisterly love and rivalry at the same time. They could compete for the attention of a certain character in the fanfic world, or they could team up to face a common enemy.
Well, they might embark on a journey to find a lost magical artifact. Since Emmett is physically powerful and Bella is quite intelligent, they could combine their skills. Emmett could handle any physical threats or obstacles, like fighting off wild animals, while Bella uses her wits to decipher clues leading to the artifact.
They could go on an adventure to find a lost family heirloom. Since they are cousins, they might be interested in their family's history. This heirloom could be a powerful magical object that has been lost for generations. Along the way, they'd face various challenges like dark magic traps and tricky riddles, with Draco using his Slytherin cunning and Luna her Ravenclaw wisdom to overcome them.
They could go on a quest to find a magical object that has the power to balance the magic in both their worlds. Since Percy is used to dealing with Greek mythology - related quests and Bella has her own experiences in the Twilight world, they could combine their skills. For example, Percy's ability to fight monsters and Bella's immunity to some vampire powers could come in handy.
Maybe they go on a journey to find a lost artifact that has the power to control both vampires and demigods. Along the way, they face various challenges like werewolves who don't want them to succeed and demigod enemies who see Bella as a threat. Percy would use her strategic thinking from her demigod training, and Bella would rely on her instincts from living in the vampire world.
They could have adventures across different dimensions. Since Loki has the ability to travel through different realms in the Marvel universe and Bella has her own experiences with the supernatural in 'Twilight', together they could explore places neither has been before. Maybe they visit a realm full of magical creatures that are a mix of vampires and Asgardians.
They could go on a journey to discover more about their family's past. Maybe there are some hidden secrets in their family tree that are linked to both the world of Greek mythology and the supernatural world of Twilight. Or they could team up to fight against a common enemy. For example, a new kind of supernatural being that is a threat to both vampires and demigods.
One possible scenario in this fanfiction is that they both have different hobbies. Bella might be into reading and Elena into painting. At first, they might be a bit annoyed by each other's hobby - related messes. But over time, they start to appreciate and even participate in each other's hobbies. For example, Elena might start reading some of Bella's favorite books and Bella could try her hand at painting, leading to a deeper bond between them.
They could have an adventure in a parallel universe. In this universe, the rules of power and combat are different. Trunks and Pan would have to adapt quickly to survive and find their way back home. It would be a story full of new challenges and discoveries for both of them.
An adventure where they have to stop an evil force that is threatening both of their worlds. Naruto could bring his knowledge of sealing jutsu to prevent the evil from spreading, and Noire could use her leadership skills to gather allies.