Common themes include protection. Harry has always been in a position of needing protection and being a protector. As Tonks' brother, he might be even more protective of her. And Tonks, with her skills as an Auror, could also be very protective of Harry. Another theme is identity. How does this new relationship change their identities? For Harry, it adds another layer to his already complex identity, and for Tonks, it might change how she's perceived in the wizarding world.
One common theme is family secrets. Since it's not part of the original story, the discovery of their sibling relationship often involves uncovering long - hidden secrets. Another is loyalty. They would show loyalty to each other as siblings in the face of various challenges in the wizarding world.
One common theme is the struggle against prejudice. Since they are an unusual couple in the wizarding world, they often face judgment from others.
One common theme is the idea of finding love in the midst of chaos. Given the war - torn world they live in, their love can be a haven. Another is the exploration of Tonks' unique abilities as a Metamorphmagus and how that adds an interesting dynamic to their relationship. For example, she might change her appearance to make Harry laugh or to show her different moods related to their relationship.
A major theme is the exploration of their unique magical abilities. Tonks' Metamorphmagus ability and Harry's connection to Voldemort are often used as plot devices. For example, some fanfictions have Tonks using her ability to help Harry in some way. Also, the theme of sacrifice is common. Since both are in the fight against the Dark side, they may have to sacrifice things for the greater good in these stories.
The theme of self - discovery is also present. Through the betrothal, Harry and Tonks learn more about themselves. They discover new aspects of their personalities, their likes and dislikes, and how they can grow as individuals while being in this unique relationship. This is often shown through their interactions with each other and how they face challenges together.
Often, there could be a theme related to Tonks' identity as a metamorphmagus and how that affects her pregnancy. Maybe she has to be careful not to accidentally change her form in a way that could harm the baby. Also, the theme of protecting the unborn child from the various threats in the wizarding world, like dark wizards or magical creatures, could be present in these fanfictions.
Common themes include the concept of finding love in unexpected places. Harry has so many different relationships in the books, and with Tonks it's an unexpected pairing. Their kiss in fanfiction can also symbolize a new beginning, a departure from the chaos and tragedy of the main story line. It can be a moment of hope and new possibilities in a world that has been filled with so much darkness.
One common theme is friendship. It shows how deep and meaningful a friendship can be between Harry and Tonks. Another theme could be healing, as Harry helps Tonks heal from emotional wounds.
One common theme is friendship. Given their age difference and different roles in the wizarding world, a platonic but strong friendship can be a central theme.
One common theme is mentorship. Tonks, being an older and more experienced witch, often acts as a mentor to Harry in many fanfictions. For example, she might teach him some advanced magic skills or how to deal with the political aspects of the wizarding world.
One common theme is the discovery of new sides of each other. Harry might see Tonks' more vulnerable side, and Tonks could understand Harry's deeper emotional traumas. Another theme is the magical aspect of their relationship. For instance, Tonks' shape - shifting ability could be used in a romantic or cute way, like changing her appearance to surprise Harry.