Common themes include the struggle between good and evil. Since Harry is the hero and Tom is the villain, their relationship in a married state in fanfiction often delves into how they deal with this fundamental difference. There's also the theme of acceptance. Harry accepting Tom's dark past and Tom accepting Harry's values. And a theme of transformation, where either Harry changes Tom or vice versa in terms of their outlooks and actions.
There are several common themes. The first is the exploration of an alternate reality. Writers create a world where Harry and Tom are married, which is very different from the original story. Another theme is the clash of ideologies. Harry's beliefs in friendship, love and justice against Tom's thirst for power and domination. And finally, there is the theme of secrecy. How they keep their relationship hidden from the wizarding community which is likely to be very hostile to their union, considering Tom's past actions.
One common theme is the exploration of good and evil. Since Tom Riddle becomes Voldemort, fanfictions often examine how Harry, as the symbol of good, could influence or be influenced by Tom. Another theme is the power of magic. Writers like to play with different magical concepts and how they might be used by Harry and Tom.
One common theme is the exploration of power dynamics. Since both Harry and Tom are powerful in different ways, in these fanfictions, when Harry is female, it adds a new layer to how they interact regarding power. For example, how a female Harry might resist or be attracted to Tom's power-hungry nature.
One common theme is the exploration of a different power dynamic. Since Harry is female, it changes the way she might interact with the powerful Tom Riddle. Another theme is the idea of redemption. Some fanfictions explore if a female Harry could be the key to Tom Riddle's possible redemption. Also, the theme of love and attraction often comes up, whether it's a forbidden love or a complex form of admiration between the two characters.
One common theme could be the exploration of an unexpected relationship between Harry and Tom. Since it's mpreg involved, it might also deal with themes of new life and how it changes their dynamic. Another theme could be the blurring of the lines between good and evil as they are brought together in this very different situation.
One common theme is the power struggle. Harry, representing the light side, and Tom, the dark side, often engage in a battle of wills and magic power. Another theme is the exploration of their shared past, like how they are both connected to Hogwarts and the wizarding world's history in different ways.
Another theme is the exploration of power dynamics. Harry has his own power, and Tom is extremely powerful in a different way. Their relationship in the fanfictions often explores how these different powers interact and whether they can find a balance in their romantic relationship. For example, in some stories, their combined powers are seen as a way to overcome greater threats in the wizarding world.
The theme of fate is also very common. The fact that they are soulmates implies a certain kind of fate. Fanfictions often explore how they are meant to be together in some way, even though it seems so unlikely given Tom's actions. For example, some stories show how their connection was predestined by magic itself.
The theme of duality is quite common. They are two sides of the same coin in a way. Harry represents light and Tom represents dark, yet they are soulmates. Fanfictions often play with this duality, showing how they can balance each other out. There's also the theme of self - discovery. Through their connection, both Harry and Tom discover new aspects of themselves that they never knew before.
Love and redemption can also be a theme. Sometimes the OC's love for someone or something makes them try to redeem Tom Riddle from his dark path. This could be a romantic love for Riddle himself, or a love for the wizarding world that makes them want to change him. It adds a layer of complexity to the relationship between the OC and Riddle.
Well, a big theme is the power struggle. Harry is seen as the 'good' and Tom as the 'evil', but being brothers adds a new dimension. Also, the theme of identity. How does being brothers change who they are? It's complex and often explored in these fanfictions. They also might explore the theme of how their upbringing could have been different if they knew they were brothers from the start.