Owen Grady would be an obvious and interesting choice. His skills with dinosaurs and his connection to Blue could be further explored. For example, he could be on a mission to rescue Blue from a new threat in the post - Dominion world.
One idea could be exploring the post - Dominion world where dinosaurs are now fully integrated into society. Maybe a story about a family who has to adapt to living next to a T - Rex nesting ground. It could be full of comical and heartwarming moments as they learn to coexist.
The back story of Jurassic World Dominion involves the dinosaurs escaping into the world after the fall of Jurassic World. Years of genetic experimentation had led to a variety of dinosaur species co - existing in a park. But disasters struck, and now they are out in the wild, creating a new and dangerous ecosystem where humans and dinosaurs must find a way to co - exist. This also ties in with the return of some original Jurassic Park characters, bringing their own experiences from the past to this new situation.
Claire Dearing is probably also a main character. She has been an important figure in the Jurassic World series. In the 'Jurassic World Dominion Novel', she may be leading efforts to deal with the dinosaur - human coexistence situation. There might also be some new characters introduced, perhaps scientists or hunters, who play significant roles in the plot, but I can't name them specifically without more knowledge of the book.
One main theme is survival. The characters have to fight to survive in a world where dinosaurs are now a dominant part of the ecosystem. Another theme could be the consequences of playing God. Humans created the dinosaurs and now they have to deal with the unforeseen outcomes of bringing these extinct creatures back to life.
The back story affects the plot as it creates the situation where dinosaurs are now a part of the world. This means the characters have to deal with them at every turn. The power struggles and mistakes from the past, as shown in the back story, lead to the various challenges the characters face in the plot, like trying to control the dinosaur population or find a way to co - exist.
Another interesting concept is a time - travel fanfic. A character somehow gets sent back in time to the pre - historic era where the dinosaurs actually lived. They have to survive in that world and try to find a way back, while also witnessing the true nature of the dinosaurs without the modern - day park's infrastructure.
One common theme could be the adventure aspect. Just like in the original 'Jurassic World' movies, the characters in the fanfic might be going through dangerous situations while also dealing with their romantic feelings. For example, two male characters might be fighting off dinosaurs while realizing their attraction to each other.
Owen Grady is a very popular choice. His skills with the raptors make for exciting storylines. Writers can explore his relationship with the dinosaurs further, or create new adventures for him where he has to use his unique bond with the raptors to solve problems in the park.
Iron Man is often popular. His high - tech gadgets and smart - aleck personality can add a lot of fun to the crossovers. He could probably come up with some crazy plans to deal with the dinosaurs. Also, Chris Pratt's character from Jurassic World, Owen, might be popular as he has experience dealing with the dinosaurs and could interact well with the Avengers.