Definitely not. Hell Boy belongs to Dark Horse Comics. Marvel Comics has its own roster of characters and storylines that are separate from Hell Boy's.
Well, a Beast Boy in a Marvel fanfic could be really interesting. He could interact with characters like the X - Men. Maybe he'd form a friendship with Beast from the X - Men due to their similar abilities. They could team up to fight a common enemy.
In a Marvel fanfic, Beast Boy could have a complex relationship with the Inhumans. His ability to change forms could be seen as both a threat and an asset. He might have to prove himself to them. Also, his connection to nature could be explored in relation to characters like Black Panther who also have a strong connection to a certain aspect of the world.
One possible fanfic could be about an original character who has a special connection with Jean Grey as Marvel Girl. Maybe the OC is a new mutant at the X - Men school and Marvel Boy, who is also there, starts to notice how the OC and Jean interact. The story could revolve around a mission where Jean's powers as Marvel Girl are crucial, and the OC and Marvel Boy have to learn to work with her.
An OC could be a villain who has a vendetta against Jean Grey as Marvel Girl and sees Marvel Boy as an obstacle. This would create a lot of action and conflict in the fanfic. The OC could have unique powers that make it a challenging opponent for both Jean and Marvel Boy.
The Avengers originated in Marvel Comics. Marvel has developed a vast universe of characters and storylines, and the Avengers are a key part of it. Their adventures have been adapted into various forms of media, including movies and TV shows.
Captain Marvel is Carol Danvers. She gained her powers through an interaction with alien technology and has become a powerful hero in the Marvel universe.