One common theme is the discovery of new powers. Takeo might have powers that are different from what the X - Men are used to, and the story could revolve around how they all figure out the extent of these powers.
The theme of redemption can also be present. Maybe one of them has a troubled past, and through their relationship with the other, they find a way to redeem themselves. It could be that nikolai has made some mistakes in the past, but takeo's influence helps him to become a better person, and vice versa. This adds an interesting layer of depth to their relationship in the fanfiction.
There might be a 'Takeo X Men fanfic' where Takeo has a special power that the X - Men need to combat a new and powerful enemy. For example, if Takeo can control time in some way, it could add an interesting dynamic to the X - Men's battles and strategies. Writers often create these crossovers to explore new relationships and plotlines within the existing X - Men universe.
One common theme is redemption. Given Archangel's complex past and his sometimes - dark actions, many fanfics explore his journey to make up for his mistakes. Another theme is self - discovery. He has to figure out how to fully control his powers and what his role is within the X - Men.
Love against all odds is a big theme. In the X - Men world, there are so many external threats and internal differences among the mutants. In gay X - Men fanfic, this often translates into two characters from different factions or with different powers falling in love. It's about how they overcome the barriers between them. Also, the theme of acceptance within the mutant community is often explored, as homosexuality might be just another form of 'difference' that the mutants have to deal with.
One common theme is Logan's struggle with his past. His long and often violent history haunts him in many fanfics. Another theme is his relationships with the other X - Men. Whether it's a friendship, a rivalry, or a mentorship, these relationships are often explored. And of course, his berserker rage and how he tries to control it is also a popular theme.
In X Men Annie Brother fanfic, family is a big theme. Their relationship as brother and sister is at the center. They might struggle with the fact that they are mutants and how that affects their family bond. Another common theme is the search for identity. They are not only mutants but also siblings, and they have to figure out who they are in relation to each other and to the X - Men community. There could also be themes related to friendship within the X - Men group, as their relationships with other mutants can influence their own relationship as siblings.
One common theme is self - discovery. The original characters often have to figure out their powers, where they fit in the mutant world, and who they are as a person. Another theme is acceptance. They may face rejection from the X - Men or other mutants at first because they are different or new. Friendship is also a big theme. As the OC gets involved with the X - Men, they form bonds with the existing characters. For example, in many fics, the OC becomes friends with Kitty Pryde or Cyclops and they help each other out in battles and in personal growth.
One common theme is brotherhood. Given their relation, many fanfics explore how their bond as brothers is strengthened or tested in different situations within the X - Men world.
Common themes include identity. For instance, a character from Harry Potter might question their identity when exposed to the X - Men's world of mutants. Also, the concept of good vs. evil is often explored. The villains in both universes, like Voldemort and Magneto, have different ideologies, and fanfics might play with how the heroes from both sides come together to fight a common foe. There's also the theme of friendship, as characters from both series form new alliances and relationships.
In 'Scott Sick X - Men Fanfic', a prevalent theme is the struggle between his physical state and his mental state. Physically being sick can take a toll on his mental well - being. He may experience doubts about his abilities and his future with the X - Men. Also, the theme of the X - Men's loyalty to him during this tough time is often explored. They have to decide how much they are willing to sacrifice to help him get better and what lengths they will go to protect him while he's in a weakened state.