There could be a power struggle. If a character has both bloodlines, they might have to deal with the internal conflict of two very different power sources. For example, Naruto's chakra is related to his spiritual and physical energy, while Spiderman's powers are more scientific - based. The character would need to find a balance.
The fanfic could involve a crossover of the two worlds. Spiderman's New York City could be invaded by Naruto - style ninjas, or Naruto's Hidden Leaf Village could be visited by a web - slinging hero. The bloodline aspect would play a role in how the characters interact and fight. Maybe the ninjas are interested in the unique powers of Spiderman's bloodline, and vice versa.
In such a fanfic, Naruto might find that his bloodline unlocks a new form of chakra. For example, his normal blue chakra could transform into a more powerful and unique - colored chakra, like purple. This new chakra could have different properties, such as being able to break through any jutsu defenses more easily. As he leaves Konoha, he has to quickly learn to control this new power on his own, without the guidance of his former teachers.
Well, it could start with Naruto seeing the dark side of bloodline powers being misused. So he decides to take matters into his own hands and develop a method to destroy bloodlines. This could lead to a huge rift in the ninja community, with some supporting him for trying to create equality and others opposing him because they value their unique family abilities.
Well, in such a fanfic, the Avengers could initially be skeptical of Spiderman. Maybe they think he's too young and inexperienced. But then Spiderman could prove himself by using his unique web - slinging skills to save one of the Avengers from a tricky situation. And they start to see his potential and welcome him to the team.
He could find a new home. For example, he might stumble upon a hidden village that accepts him for who he is and his powerful bloodline. There, he could train and become even stronger.
In this fanfiction, Naruto getting the Uzumaki bloodline could lead to him having a stronger connection to his family heritage. It could also mean he has better control over his life - force energy, which is something the Uzumaki clan is associated with. Maybe he could even unlock some unique Uzumaki - only jutsus that no one has seen in a long time.
Well, one possibility is that Naruto's new bloodline power could attract various female characters. Maybe they would be intrigued by his unique ability and want to get closer to him. For example, Sakura might see him in a whole new light and develop deeper feelings. And Hinata could be even more drawn to him, leading to some interesting romantic tension among the harem members.
Well, he could gain new and powerful abilities. Maybe he discovers a hidden bloodline within himself or through some encounter related to the new bloodline he joins. He might use these new powers to prove his worth to those who banished him.
In a fanfic about a Spiderman field trip, it could be that the field trip is to Oscorp. There, Spiderman discovers some unethical experiments. He has to then figure out how to expose the wrongdoings without revealing his identity to his classmates who are also on the field trip. He might use his wits and web - slinging abilities to gather evidence secretly.
Well, he might gain some really cool and spooky powers. Maybe he could have the ability to manipulate souls like the Shinigami does. This could give him an edge in battles, being able to directly attack an opponent's soul or use soul - based defenses.
In a Black Cat unmasks Spiderman fanfic, there could be a lot of drama. Maybe Black Cat unmasks him during a fight and is shocked to see Peter Parker. This could lead to her having to decide whether to expose him or keep his secret. It might also create a more complex relationship between them, with her using the knowledge to her advantage in some way.