Well, in such fanfics, the writers often take the close relationship of the twins and expand on it in a romantic way. They might describe secret glances or special moments between them that are exclusive to their relationship. It could also involve how the other host club members react to this new aspect of their relationship, whether they are accepting or confused.
Often, the fanfics will play up their differences and how those differences complement each other in a romantic sense. For example, if one twin is more outgoing and the other more reserved, the fanfic might show how they balance each other out. Also, the host club setting is used to create interesting scenarios. Maybe they have to hide their relationship from the clients at first, which adds a layer of secrecy and intrigue.
A fanfic with this scenario could start with Harry arriving at Ouran Highschool on a rainy day. He has his trusty umbrella, which could be a family heirloom or a magical item. As he walks through the school grounds, the students of Ouran Highschool are intrigued by his different appearance and the old - fashioned umbrella.
Well, there could be a love story between Kyoya and a new girl who joins the school. The girl is a bit of an enigma. Kyoya, always the calculating one, tries to figure her out for the sake of the Host Club's business. But as he digs deeper, he discovers her real charm. She challenges his cold - hearted business - like approach to things. They start having little debates and gradually, Kyoya finds himself looking forward to seeing her every day. His feelings grow from mere curiosity to love, and she also starts to see the warm - hearted person beneath Kyoya's calculating exterior.
One possible plot for such a fanfic could be that on a rainy day at Ouran Highschool, a character similar to Harry (maybe with some of his traits) shows up with a special umbrella. The umbrella might have some magical powers related to the rain, like creating a rain - free zone around the holder. And this character could interact with the Host Club members in unique ways because of this umbrella.
There could be a story where the relationships between the characters in 'Ouran Highschool' are explored in a more emotional and deep way in the fanfiction. For example, how two characters overcome their differences and form a strong bond. It might show their growth and development in a new light compared to the original story.
The male OC could be an undercover journalist. He joins the host club to expose the so - called 'extravagant lifestyle' of the rich students. As he spends more time in the club, he starts to understand the real personalities behind the hosts and realizes that there's more to them than just their wealthy facades. This could lead to a story full of self - discovery and unexpected friendships.
One idea could be an OC who is a new transfer student at Ouran. She's a bit of a tomboy and accidentally stumbles into the Host Club room while looking for the library. The Host Club members are intrigued by her unique style and she ends up becoming a regular visitor, slowly forming a special bond with Tamaki. She could introduce them to new hobbies like skateboarding.
Also, 'Ouran Highschool OC Fanfiction' provides a platform for fans to explore different themes and ideas. The original series has a certain set of themes, but with OCs, fans can introduce new concepts such as a different cultural background for the OC which can lead to interesting discussions about diversity within the Ouran world. It also allows for different interpretations of the existing characters based on how they interact with the OC.