One common theme is the clash of modern and medieval values. Danny, coming from a modern world, often has to deal with the more traditional and sometimes strict values of the medieval era. For example, concepts like chivalry and honor are things he might not be familiar with but has to learn.
Another theme is the use of Danny's powers in a medieval setting. His ghost powers are a huge advantage in a world that lacks modern technology. Fanfictions often explore how he uses these powers to solve problems or gain an edge in battles against medieval villains.
Adventure and exploration are also common themes. Danny and his friends (if they are also in the story) usually embark on adventures in the medieval world. They might explore ancient castles, encounter mythical creatures, or get involved in political intrigues within the medieval kingdoms, all while Danny tries to figure out how to get back to his own time or deal with the new situation he's in.
One common theme is family. Since they are siblings, a lot of fanfics explore their family bond, like how they rely on each other and protect one another. Another theme is secrecy. Danny has to keep his ghost identity a secret, and Jazz often gets involved in that secrecy, either by helping him keep it or by accidentally finding out. Growth is also a theme. As the story progresses, both Danny and Jazz grow as characters, both in their personal lives and in dealing with the supernatural elements around them.
One common theme is the power struggle. Ember has her own set of powers and often tries to overpower Danny, either for her own gain or just for the fun of it. So there's a constant back - and - forth in terms of who's in control.
One common theme is the exploration of their relationship. Whether it's a friendship or a budding romance, it's often at the center of the story. For example, in many fanfictions, Danny tries to protect Paulina from ghosts, which shows his care for her.
One common theme is the relationship between Danny and Kitty. It often explores their dynamic, whether it's a budding romance or a complex friendship.
A common theme is the struggle between good and evil within Danny himself. Since Dark Danny is Danny's dark side personified, it's all about Danny facing his own inner demons. For example, in many fanfictions, Danny has to deal with the temptation to give in to the power that Dark Danny represents.
A frequently seen theme is the power of friendship evolving into love. They start as friends who understand each other's quirks and then it blossoms into something more. Also, the theme of sacrifice is there. In some fanfics, either Sam or Danny is willing to sacrifice something important, like Sam giving up some of her ideals or Danny risking his secret identity, for the sake of their relationship.
In 'Danny Phantom Danny x OC fanfiction', a prevalent theme is self - discovery. As Danny and the OC interact, they both learn more about themselves. For instance, the OC might help Danny understand a different perspective on his powers. Also, the theme of acceptance is common. Danny has to accept the OC into his rather strange world of ghosts, and the OC has to accept Danny's dual identity. And friendship is also a key theme that often leads to a deeper romantic relationship between them. They start as friends or at least allies and then their relationship grows.
One common theme is exploring Danny's relationship with his mother in the context of his secret identity as Danny Phantom. It could be about how she might react if she found out, or how she unknowingly influences his actions as a hero. Another theme could be family dynamics, like how Danny's mother's presence affects his relationships with his friends and other family members in the Phantom world.
One common theme is the struggle between Danny's two identities - his human self and his ghost self - in relation to his romantic relationships. For example, he might worry about putting his love interest in danger because of his ghost - fighting activities.
Power dynamics is also a common theme. Danny has his ghost powers and in Gotham, there are various power - hungry villains and powerful heroes. How Danny fits into this power structure or disrupts it is often explored. For instance, he might have to figure out how to deal with Batman's no - kill rule while also dealing with his own enemies who are not bound by such moral codes.