Love and friendship are also common themes. Some fanfictions explore a romantic relationship between Tom and the male oc, while others focus on a deep friendship that could potentially change Tom's fate. It's interesting to see how these relationships are developed against the backdrop of Tom Riddle's darkening path in the wizarding world.
One common theme is the exploration of power. Since Tom Riddle is power - hungry, the male oc often gets involved in his pursuit of power in different ways, either as an ally, a rival, or someone trying to change him.
Another theme is the exploration of Tom Riddle's character. The OC serves as a tool to dig deeper into what makes Tom the way he is. Through his possessive actions towards the OC, we can see his insecurities, his thirst for power, and his disregard for others' feelings. Writers often use this as a way to expand on the already complex character of Tom Riddle in the context of fanfiction.
Redemption is a common theme. Since Tom Riddle later becomes Voldemort, many fanfictions with an oc adopting him focus on whether he can be redeemed through the love and care of the oc. Another theme is the power of family. The oc often tries to create a family - like environment for Tom, which is something he lacks in the original story.
One common theme is the struggle between good and evil. Since Tom Riddle Jr. is on his path to becoming Voldemort, the OC often has to decide whether to support his darkening ways or try to turn him towards the light. Another theme is the exploration of Tom's past. The OC may dig into his family history or his time at Hogwarts before he fully embraced the dark arts.
Love in the face of darkness is a big theme. Despite Tom Riddle's evil tendencies, the oc wife falls in love with him, and the story explores how that love can survive. Also, secrecy is often a theme as Tom Riddle has many secrets that the oc wife slowly discovers throughout the story.
The theme of mystery is quite common in these fanfics. Given Tom Riddle's mysterious nature, the oc often gets drawn into solving the mysteries around him. It could be about his past, his plans, or his real intentions. Additionally, the theme of friendship is also present in some 'tom riddle and oc fanfic'. The oc might try to befriend Tom Riddle, thinking they can change him through friendship, which leads to a series of events that show the complexity of such a relationship.
Power struggle is also quite prevalent. The OC often has some sort of power or knowledge that either challenges or complements Tom Riddle's own power. For example, the OC could be a seer, and their visions of the future clash with Riddle's plans. This creates a tense dynamic throughout the story.
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.
One common theme is power. Since Tom Riddle is obsessed with power, the male oc often gets involved in his power - seeking journey either as an obstacle or an enabler. Another theme is identity. The male oc usually has his own unique identity which clashes or meshes with Tom's complex identity.
His relationship with other characters is also a common theme. For example, how he interacts with Dumbledore or his classmates at Hogwarts. Some fanfictions also focus on his inner turmoil, the conflict between his human side and the dark side that is growing within him.
One common theme is power struggle. Tom Riddle often has a thirst for power, and when he crosses over into other worlds or stories, he may face new challenges or rivals for power. Another theme is the clash of cultures. His own dark and calculating nature from the Harry Potter universe may contrast with the values and norms of the new world he enters. And identity exploration can also be a theme. As he experiences new things, he might question who he really is.