Perhaps they are tired of the constant power struggles and drama. Bella has seen a lot of chaos in the vampire world, and Jasper has been through it for a long time. Together, they decide to run away to find some peace. They want a life away from the battles, the territorial disputes, and the never - ending family feuds. They believe that by running away, they can start anew and build a more harmonious existence for themselves.
One possible plotline could be that they run away to escape the complex vampire politics in their world. Maybe they find a secluded place, like a remote island, and try to build a life there. They might face challenges such as hiding their presence from other vampires and dealing with their own internal struggles about leaving their families and friends behind.
They might run away because they want to explore the wizarding world on their own terms. Without the restrictions of Hogwarts or the watchful eyes of the Ministry of Magic.
Love. Naruto may finally realize his true feelings for Hinata and want to be away from the chaos of the village to be with her in peace.
They might choose to run away because they want privacy. After all the battles and saving the world multiple times, they just want some time alone without any interruptions from other demigods or the gods. So running away seems like a good option.
Maybe for love. They might have fallen deeply in love and want to be away from the prying eyes of the wizarding world.
Perhaps in the fanfiction, Ciel discovers some dark secrets about the Phantomhive family or the underworld they are associated with that are so disturbing that he decides to run away. He wants to distance himself from all the evil and corruption, hoping to find a place where he can be free from all the burdens that come with his family name.
There are several possible reasons. Firstly, a sense of being controlled. If Edward is constantly making decisions for her or restricting her actions, Bella would want to break free. Secondly, self - preservation. If she realizes that the relationship is putting her in more danger than she can handle, she'll run. Thirdly, a change in her feelings. Maybe she falls out of love with Edward or realizes she was never truly in love, but rather in some sort of infatuation. So, she runs away to sort out her emotions and her life.
They might run away to avoid a conflict that their villages are about to be dragged into. Naruto and Sasuke, being the powerful ninjas they are, don't want to be used as tools in a war, so they decide to run away.
Some fans like it because it offers an alternative to the canon relationships. It gives a chance to explore a different dynamic between Harry and Hermione, one that might be more romantic or at least a very deep friendship that's different from what's shown in the books. It allows for creativity and new storylines.
They might choose to run away secretly because they want to be alone together. They are in love, and the hustle and bustle of Hogwarts life doesn't give them enough privacy. So, they run away to a quiet place where they can enjoy each other's company without any interruptions.