Here are some plot ideas. The normal human OC could be a food blogger who accidentally discovers a ghoul - friendly restaurant that serves food made from non - human sources. This leads to a series of adventures as they try to keep the restaurant's secret while also trying to promote the idea of co - existence. Or the OC could be a young child who befriends a ghoul puppy (yes, a ghoul in puppy form if we get creative) and through this friendship, tries to change the world's view of ghouls. Also, the OC could be a historian who uncovers an ancient prophecy about the end of the ghoul - human war and sets out to fulfill it.
One plot idea could be that the normal human OC discovers a secret organization that is trying to create a peace treaty between ghouls and humans. The OC gets involved in the negotiations, facing opposition from both sides. Another idea is that the OC is a detective who is investigating a series of ghoul - related murders and ends up getting too close to the truth and becomes a target. Or perhaps the OC is a doctor who tries to find a way to make ghouls live without having to eat humans.
A good plot could involve a human OC who is a doctor. They end up treating a ghoul who was severely injured in a fight. This starts a strange relationship where they try to understand the nature of ghouls better. As they get more involved, they learn about a secret organization within the ghoul world that is planning something big that could endanger all of Tokyo. The OC then has to decide whether to stay out of it or try to stop it. It's a plot full of moral dilemmas and action. Also, a plot where the human OC is an artist and they use their art to show the hidden side of the ghoul - human relationship could be interesting. Their art could either be a way to promote peace or it could stir up more trouble depending on how different groups react to it.
One plot idea could be your OC being a new ghoul trying to find their place in the ghoul society. They might start at the bottom, having to learn the rules of the different ghoul groups and facing discrimination from more established ghouls. Another idea is that your OC discovers a secret about their transformation that no one else knows, like it was part of a secret experiment by the CCG. They then have to figure out what to do with this knowledge while also avoiding being caught by the CCG.
To create a good Tokyo Ghoul normal human OC fanfiction, start with a strong concept for your OC. They could be a journalist trying to expose the truth about ghouls, or a student who accidentally discovers the ghoul underworld. When writing, focus on their emotions. Fear is a big part of the Tokyo Ghoul world for normal humans. Show how they react to the danger around them. You can also include elements of growth. Maybe they start off as a coward but become a hero in the end. Don't forget to keep it in line with the overall tone and lore of Tokyo Ghoul.
Some plot ideas for Tokyo Ghoul female OC fanfiction include her being an outcast among ghouls due to her different beliefs. Maybe she believes in non - violence and tries to spread this message, which goes against the traditional ways of many ghouls. Or, she could be on a quest to find out the truth about her transformation into a ghoul. Was it an accident, or was she targeted? This could lead her to uncover secrets about the ghoul world that have been long buried.
You could create an OC who is a ghoul investigator from a foreign country. This OC would bring different techniques and perspectives to the fight against ghouls. They might also face discrimination or misunderstanding within the Tokyo Ghoul universe due to being an outsider. For example, they could have a special weapon or training method that the local investigators haven't seen before.
One idea could be to explore the backstory of Rize's brother. Maybe he was involved in some secret ghoul society before Rize became known. You could start with a scene where he is on a mission for this society, which then ties into how Rize's life is affected.
When creating a human OC for Tokyo Ghoul fanfiction, consider the world they live in. Tokyo in the Tokyo Ghoul universe is a dangerous place. So, your OC should have some way to adapt. They could be a detective in training, learning about ghouls to protect the city. Their character arc can be about how they grow from being naive to being a real force against the ghoul threat. You can also add some mystery to their character. Maybe they have a hidden power or a past that they themselves are not fully aware of, which slowly unfolds throughout the fanfiction.
Another aspect could be his relationships. He might have a complicated friendship with a human who is aware of his ghoul nature. This relationship could be full of tension, as they both try to navigate the dangerous world where ghouls and humans are at odds.
One important aspect is the plot. It can't just be about the OC collecting a bunch of characters for a harem. There should be a real story, like maybe the OC is on a mission to change the relationship between ghouls and humans and the harem members are either helping or hindering that. The fanfiction should also stay true to the overall tone of Tokyo Ghoul, which is often dark and gritty.
A good plot also involves character growth. Have your male OC start as a naive ghoul and through his experiences, he becomes more cunning and powerful. This transformation can be the heart of the fanfiction, as readers watch him overcome obstacles and change for the better.