A common theme is redemption. Some fanfictions explore the idea that Tom, as Harry's father, could be redeemed through his relationship with his son. Also, the theme of family secrets is often present. Harry discovers things about his family that he never knew before, which changes his perspective on himself and the wizarding world.
One common theme is identity. Harry has to come to terms with being the son of Tom, who might be a controversial figure. Another theme could be power. Since Tom is often associated with dark magic and power, it's explored how Harry might be influenced by that.
One common theme is identity crisis. Harry has to deal with being the son of the most evil wizard. Another is power struggle. Since he's related to Voldemort, there are often plots about whether he'll inherit dark powers or not.
A prevalent theme is the struggle against the dark side. Given his father's history, he may constantly face the temptation of dark magic. He might also face prejudice from others who know his father's deeds. This could lead to a theme of isolation and his journey to overcome it, to prove that he is not like his father.
Another theme is redemption. Some fanfictions like to explore if Tom could be redeemed through his relationship with Harry. It gives a new perspective on the character of Tom Riddle.
Well, a frequent theme is the exploration of family. Harry has always been an orphan, and suddenly finding out he's Tom Riddle's son would completely redefine his understanding of family. There could also be themes related to the battle between good and evil within himself. Since he has the blood of a dark wizard, he may have to constantly fight against his darker instincts. Also, the theme of acceptance by the wizarding world could be present, as they may be hesitant to accept someone with such a dark heritage.
One common theme is the power dynamic. Since both Harry and Tom are powerful in different ways in the Harry Potter universe, fanfictions often explore how their powers interact when they are mates. For example, Harry's ability to resist the Dark Arts might contrast with Tom's inclination towards it.
In these fanfictions, the theme of acceptance is quite common. They have to accept each other as brothers despite their differences. Also, the exploration of the past is a big theme. Digging into their family's past to understand why things are the way they are in their present. And there's always the theme of adventure as they go on various magical adventures together as brothers.
Power dynamics can also be a theme. Given the nature of the characters Harry and Tom from the original source, their power relationship might be re - examined in these fanfictions, especially considering the added element of mpreg which can change the balance in different ways.
One common theme is family. Since they are brothers in these fanfictions, the idea of family loyalty, love, and conflict within the family unit is often explored.
One common theme is redemption. Since Tom is often seen as a villain in the original story, in these fanfictions, the soulmate bond can be a way for him to find redemption through his connection with Harry. Another theme is the power of love and connection, which is strong enough to bridge their differences.
Another theme is the exploration of their changed relationship. They may have been enemies before, but in the reborn scenarios, they could become friends or at least allies. It's like in some fictions where they team up to face a greater threat that was overlooked in their previous lives. They learn to understand each other's motives better.