One idea could be that Bella is forced into the wedding with Demetri due to some vampire politics. But as time goes on, she discovers a softer side to Demetri that she didn't expect. Another could be a time - travel plot where Bella from the future comes back to stop the wedding but ends up falling in love with Demetri in the past. Or perhaps there's a mix - up where Bella thinks she's marrying Edward but it turns out to be Demetri at the altar, and then they have to figure out their relationship from there.
Well, a plot could involve Demetri being cursed and the only way to break it is to marry a human, which is Bella. At first, Bella is terrified but as she gets to know Demetri better during the wedding preparations, she starts to have feelings for him. Also, a great plot would be that all the vampires from different covens gather for the wedding and there are some power struggles and rivalries that Bella and Demetri have to navigate together, which in turn strengthens their bond.
For the 'Bella and Demetri Wedding Fanfiction', a possible plot is that Bella has lost her memory and Demetri takes advantage of this to marry her. However, as she slowly regains her memories, she has to decide whether to stay with Demetri or go back to her old life. Another idea is that there is a prophecy that says Bella and Demetri's union will bring peace between the vampires and werewolves. So, they get married under this great pressure but find true love along the way.
Maybe in a fanfiction, Demetri discovers that Bella has a hidden power that not even the Cullens are aware of. He then has to decide whether to report it to the Volturi or keep it a secret and help her develop this power. This could create a complex relationship between them, full of trust issues and moral dilemmas.
In some fanfictions, Bella could be turned into a vampire by Demetri in a rather unorthodox way. This new vampire Bella then has to navigate the complex vampire society with Demetri as her guide. He teaches her how to use her new abilities and they end up having a deep bond that is more than just a typical vampire - human relationship.
One idea could be Demetri getting caught in the middle of a Hogwarts mystery. Maybe he's sent on a mission by the Death Eaters that somehow intersects with Harry's search for a Horcrux. Another could be a story where Demetri has a change of heart and decides to help Harry, seeing the error of Voldemort's ways.
One idea could be Demetri and Leah teaming up to protect the Forks area from a new threat that neither the vampires nor the werewolves have faced before. They might start off as reluctant allies but gradually develop respect for each other.
One idea could be a story where Demetri and Heidi are sent on a secret mission by the Volturi. They have to infiltrate a group of rogue vampires who are causing chaos in a small town. Along the way, they start to question their loyalty to the Volturi as they see the good in the town's people.
One idea could be that Jane and Demetri are sent on a secret mission by the Volturi. They have to infiltrate a group of vampires who are suspected of planning an uprising against the Volturi. Along the way, they start to question their loyalty to the Volturi as they see the other vampires' reasons for wanting change.
Jacob and his werewolf pack could be antagonists. Since Bella has a history with Jacob and the werewolves don't really trust the vampires, they might oppose the wedding. They could try to disrupt the wedding to keep Bella from marrying Demetri, believing it's not in her best interest.
One idea could be that they have the wedding in a secluded forest clearing. The trees are adorned with twinkling lights and white flowers. Bella's dress could be a simple yet elegant lace creation. Edward could surprise her with a song he composed especially for their wedding day.
Well, in some fanfiction, they might focus on the conversation they have. They could talk about their future, their hopes for a family. Also, it could be about how they finally feel completely at ease with each other. Like Edward might show Bella some of his old family heirlooms and tell her the stories behind them, which makes their connection even deeper on this special night.
One possible plot twist could be that an old enemy shows up at the wedding. For example, a vampire from a different coven who has a vendetta against either the Cullens or the werewolves. Another could be that Jacob has a premonition right before the wedding that something bad will happen to Bella in the future, which makes him hesitant to go through with it. Or perhaps a long - lost relative of Bella's arrives and reveals a big family secret that shakes things up.