One common theme is the struggle for identity. The male reader often has to figure out whether they are more human or more ghoul. For example, in many fanfics, they might have human emotions but also the uncontrollable urges of a ghoul.
Survival is also a big theme. In the Tokyo Ghoul world, it's dangerous for both humans and ghouls. The male reader has to find ways to stay alive, whether it's by hiding their true nature or by fighting against those who would harm them. This could involve battles with other ghouls or escaping from ghoul investigators. And they often have to make tough choices about who to trust.
The theme of forbidden love often comes up as well. In the Tokyo Ghoul universe, the relationship between a ghoul and a human is generally not accepted. So, in Nishiki x Reader fanfictions, there's often the tension of this forbidden love, with the two having to hide their relationship from others, whether it's other ghouls or the CCG.
Yes, it is quite common. Fans are always eager to explore more of the world they love, and fanfiction provides an opportunity to do that.
Power struggle is a common theme. You have the super - powered beings from Prototype and the ghouls from Tokyo Ghoul, all vying for control or survival in a merged world.
One common theme is the struggle for identity. Female Kaneki, being both human and ghoul, constantly has to figure out who she really is. This is often explored through her interactions with both humans and ghouls, and how she feels like she doesn't fully belong to either group.
One common theme is power combination. Since both Naruto and Tokyo Ghoul have unique power systems, fanfics often explore how the ninja techniques and kagune powers can be used together. Another theme is the clash of cultures. The shinobi way from Naruto and the harsh reality of the Tokyo Ghoul world are very different.
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.
One common theme is the struggle between the human and ghoul nature. The OC Ripper, being an original character in the Tokyo Ghoul universe, often has to deal with the duality of having human emotions and the blood - thirsty instincts of a ghoul. Another theme could be isolation. Since ghouls are hunted and feared, the OC Ripper might find themselves alone, not fully belonging to either the human or ghoul society. Also, themes of revenge can be present. Maybe the OC Ripper has a past filled with pain caused by humans or other ghouls and is seeking vengeance.
One common theme is the struggle between two different worlds. Since Harry Potter and Tokyo Ghoul have very different settings, the fanfictions often explore how a female Harry Potter would adapt to the dark and dangerous world of Tokyo Ghoul. Another theme could be power and identity. How does her magical abilities from the Harry Potter world interact with the kagune powers in Tokyo Ghoul? And how does she redefine her identity in this new context.
Another theme is the search for identity. Ghouls in the fan fictions often question who they are, especially those who have some human connections or memories. For example, a ghoul who was once human might struggle with their new identity.