Redemption can be a theme as well. Kaneki has a lot of guilt from his past actions, and in some fanfics, Touka helps him find redemption. Their relationship becomes a source of healing for him, and they grow together in the process of him coming to terms with his past.
Love and acceptance are very common themes. Given that Kaneki is a half - ghoul and Touka is a full ghoul, their relationship often explores how they accept each other's differences.
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.
Common themes in fanfictions about their love include growth. Both Kaneki and Touka grow as individuals because of their relationship. They become more empathetic and stronger. Another theme is the exploration of the forbidden. Their love is a bit of a taboo as a ghoul - human relationship (even though Kaneki is half - ghoul). It adds an element of excitement and danger to their story. And unity is also a theme, as they unite against the forces that try to tear them apart and the discriminatory world around them.
The theme of friendship in the face of adversity is quite common. They are in a world full of conflict between ghouls and humans, yet they form a connection. There's also the theme of sacrifice. In some fanfics, one may sacrifice for the other to uphold their new - found relationship or to protect the greater good in the Tokyo Ghoul universe.
One common theme is the exploration of their complex relationship. Given their different personalities and backgrounds within the Tokyo Ghoul universe, fanfics often focus on how they interact, whether it's a love - hate relationship or a gradual understanding and acceptance.
There's 'Under the Moonlight'. This fanfic focuses on the more emotional side of their relationship. It shows Kaneki and Touka dealing with their past traumas while falling deeper in love. It has great character development and some very touching scenes that will make any fan of the couple happy.
Kaneki and Touka could be in a situation where they have to team up with some former enemies to save the ghoul community from a new threat. This would test their ability to forgive and their leadership skills within the community.
One common theme could be the exploration of their complex relationship. Given their characters' backgrounds and the story they come from, fanfics might delve into how they navigate their feelings for each other in a more intimate context.
One possible scenario in a fanfiction could be that after a long and arduous battle against the CCG, Kaneki and Touka find a moment of peace. They look into each other's eyes, realizing how much they've been through together. Then, slowly, Kaneki leans in and their lips meet. It's a tender and passionate kiss that symbolizes not only their love for each other but also their hope for a better future in the dark world of Tokyo Ghoul.
In fanfiction, Kaneki and Touka's love is often portrayed as a deep and complex bond. They've both been through so much trauma in the Tokyo Ghoul world. Their love can be seen as a source of healing for each other. Kaneki, with his internal struggles, finds solace in Touka's strength and determination. Touka, on the other hand, is drawn to Kaneki's kindness beneath his tortured self. Fanfic writers explore how they support each other, grow together, and face the challenges of their ghoul - human coexistence world side by side.
A fanfiction might explore the idea of Kaneki and Touka's married life in a more comical way. Maybe they argue about who does the dishes, as ghouls don't really have normal eating habits. Or they have to deal with their friends constantly dropping by unannounced. Their relationship would still be full of love, but these little everyday situations would add a touch of humor to their married life.