Morticia could be a vampire in this fanfiction mash - up. Her alluring and mysterious nature would fit right in with the Twilight vampires. She could have her own coven, separate from the Cullens, and perhaps there would be a rivalry or an alliance formed between them based on her interactions with Carlisle. She would bring her own sense of style and elegance to the vampire world, along with the Addams family's penchant for the macabre.
Sasuke could be seen as a kind of dark and brooding figure that the Addams Family might respect. His quest for power and revenge could be something they find interesting. Naruto, on the other hand, with his bright and positive attitude, would be a contrast to the Addams Family's usual aesthetic but could bring a new kind of energy to their world.
The Addams Family could fit into Gotham's universe in many ways. For example, they could be seen as an eccentric family living on the outskirts of Gotham. Their macabre interests and strange behavior might be misinterpreted by the citizens of Gotham as something more sinister. Gomez could interact with some of Gotham's mobsters in a very unique way, perhaps out - of - the - box business deals. Morticia's elegance and mystery would add a different kind of charm to the dark city. And Wednesday, with her penchant for the morbid, could find Gotham a rather interesting place to explore, especially with all the dark alleys and strange characters.
The Addams family could fit into the wizarding world by bringing their own sense of style and values. Their mansion could be a place where students go for a different kind of magical experience. They might hold parties where they showcase their strange magical artifacts. In terms of the Hogwarts houses, they might not fit the typical mold. Wednesday could be a unique Slytherin who doesn't care about the pure - blood - mania but rather about her own personal power. Pugsley could be a Hufflepuff who is loyal to his family's odd ways. And the family as a whole could contribute to the diversity of the wizarding world.
You can start by finding common traits. For example, both worlds have characters that are outsiders in a way. The Cullens in Twilight are different from normal humans because they are vampires, and the Addams family is different from the average family with their love for all things dark and spooky. So, you could have a situation where they recognize this similarity in each other.
Perhaps Harry is a new neighbor in the Addams Family's neighborhood in the fanfiction. He starts off as an outsider but gradually gets drawn into their strange world. He could be intrigued by their unique lifestyle and they, in turn, might be interested in his different perspective. He could end up becoming a part of their family - like circle, joining in on their unusual family activities such as séances or midnight picnics in the cemetery.
Joker would probably see the Twilight world as a new playground. He might try to mess with the Cullens, seeing them as too 'perfect' and in need of some chaos. Harley, on the other hand, could be fascinated by the idea of eternal love in the Twilight series. She might even try to get involved in the relationships, perhaps causing some jealousy or misunderstandings.
She might fit in as an outcast at first. Her gloomy appearance and attitude would set her apart. But she could gradually find her niche. Maybe she'd excel in Defense Against the Dark Arts, as she has her own experience with the darker side of life.
Morticia would likely be intrigued by Harry. She might be drawn to his mysterious past in the wizarding world and his magical abilities. Gomez, on the other hand, would probably be excited to have a new family member to share his adventures with. Wednesday might see Harry as an interesting addition, someone who could bring a different kind of darkness to the family. And Pugsley might look up to Harry, especially if Harry shows him some cool magic tricks.
Harry Potter and his friends would be both shocked and intrigued by the Addams family. Ron would be constantly freaked out by their strange habits, like Gomez's love for knives and Morticia's long black hair that seems to have a life of its own. Hermione, however, would be eager to learn about their family magic, if they have any. She might try to study it like she does with other forms of magic in the wizarding world. And Harry would probably be a bit cautious but also curious, seeing as he has his own experience with dark and strange things.
Finn would likely be a very determined participant. His strong sense of justice would make him oppose the killing game wholeheartedly. He might try to find a way to escape and take as many people with him as possible. Jake, on the other hand, could use his shape - shifting abilities to protect himself and others. He could turn into a shield or a large beast to fend off attackers.