A lot of these fanfictions also explore the theme of love. Kaneki's love for his unborn child and the love he receives from others are often central. It shows how love can grow and evolve during this special time in his life. For example, in some stories, his relationship with his partner deepens as they share this experience together.
One common theme is identity struggle. Since Kaneki is a complex character, when he's put into different universes in crossovers, he often has to re - evaluate who he is. For example, in a crossover with a superhero universe, he might question whether he can be a hero or if his ghoul nature makes him an outcast.
One common theme is the exploration of their complex relationship. Given their different natures, fanfictions often focus on how they come to understand and accept each other. For example, Tsukiyama's initial predatory nature towards Kaneki and how that changes over time.
A common theme is redemption. Since both characters have done things they're not proud of in the original story, many fanfictions explore their journey towards redemption through their relationship with each other.
A common theme is romance. Since Ken Kaneki is a complex and interesting character, many female - authored fanfictions explore a romantic relationship between a female character and him. Another theme is friendship. Female characters might form deep friendships with Ken Kaneki and support him through his struggles. Also, self - discovery is often there. Ken Kaneki's own journey of finding out who he is as a half - ghoul can be paralleled with a female character's journey in some fanfictions.
Self - acceptance is a very prevalent theme. The two Kanekis need to come to terms with their own existence and their relationship with each other. Identity crisis is also common. They both represent different aspects of Kaneki's identity and the fanfic often explores how to reconcile these different identities. Additionally, the theme of power and control can be seen, as they may fight over who gets to be in control in certain situations.
One common theme is survival. Given the nature of their world, they often have to fight to survive together, which strengthens their bond.
The theme of redemption can also be present. Rize's actions towards Kaneki were quite cruel in the original story. Fanfictions may attempt to give her a chance at redemption, perhaps through her relationship with Kaneki. This could involve her showing remorse for what she did and trying to make amends in some way.
One common theme is love and sacrifice. Kaneki and Touken's relationship is often depicted as a deep, selfless love. They might be willing to sacrifice their own safety or desires for the other. For instance, Kaneki could put himself in danger to protect Touka from a powerful enemy.
Often, there are themes of protection and support. Given the unusual situation of mpreg, Hide might be portrayed as being very protective of Kaneki. And also, themes related to the acceptance within the Tokyo Ghoul world or their own small community could be present. Since it's an unconventional concept, how other characters react to it can be an important part of the story. Additionally, themes of love and sacrifice might be emphasized as they face difficulties together because of the mpreg situation.
One common theme is friendship. Often, the stories start with a simple acquaintance that grows into a deep and meaningful friendship. For example, they might bond over shared hardships or a common goal. Another theme is loyalty. Kaneki and the male reader usually show great loyalty to each other, standing by one another in dangerous situations.