In this fanfiction, the OC could be a detective - in - training who comes to Inaba to solve some cold cases. Yukiko gets involved when some of these cases seem to be related to the TV World. They team up, with Yukiko providing her knowledge of the town and the OC using their detective skills. As they work together, they develop feelings for each other. But they also have to deal with the danger of the Shadows and a mystery figure who seems to be controlling them, all while trying to figure out their relationship.
Maybe the OC has a special power in the TV World. Yukiko, being part of the Investigation Team, is intrigued by this. They embark on adventures together within the TV World, fighting Shadows side by side. Their relationship could develop from a simple acquaintance to a deep friendship. And along the way, the OC might teach Yukiko some new ways to use her Persona, leading to some interesting battles and character growth for both of them.
In this fanfiction, the OC could be a loner who is misunderstood by most people in Inaba. Naoto, on the other hand, is respected but also somewhat isolated because of their unique position. They meet by chance during a strange event related to the Persona world. At first, they are wary of each other. But as they start to work together to solve the mystery behind the event, they realize they have more in common than they thought. The OC helps Naoto to open up more on an emotional level, and Naoto teaches the OC how to better use their Persona powers. Their relationship gradually evolves from a reluctant partnership to a strong bond that is crucial for saving Inaba from a greater threat that is looming over the town.
A great one often has well - developed characters. It should stay true to the personalities of Yu and Yukiko from the game. For example, Yu's calm and collected nature and Yukiko's strong - willed yet sometimes shy side. Also, an interesting plot that maybe explores their relationship further, like how they support each other during the events in the TV world.
Well, an interesting plot could involve an OC that is a transfer student, just like the protagonist. But this OC has a hidden past related to the Metaverse. Maybe they were experimented on by a shadowy organization in their home country, and this gives them a different perspective on the Metaverse compared to the Phantom Thieves. Their goal could be to find out who was behind those experiments and get revenge. Along the way, they form a bond with the group and learn new ways of using their powers.
Perhaps the fanfiction focuses on the cultural clash between the two groups. The Persona 4 characters are from a small town, while the Persona 5 crew is from the big city. Their different ways of handling things and their unique Personas could lead to some interesting interactions. For example, Yu and Joker might have different leadership styles that they have to reconcile in order to succeed against the shadows.
The fanfiction could revolve around a new character who has the ability to traverse between the Splatoon and Persona 5 worlds. This character discovers a conspiracy that if not stopped, will merge the two worlds in a disastrous way. The character enlists the help of both the Inklings and the Phantom Thieves. They have to overcome their differences in fighting styles and cultures to save both their worlds. The inklings' turf war strategies could be adapted to the battles in the Metaverse, and the Phantom Thieves' stealth could be useful in the Splatoon world.
One plot idea could be that the male OC from Persona 4 is a transfer student to Inaba. He meets Rise during some sort of community event. Their relationship starts off as friendly but slowly develops into something more as they discover they both have a connection to the world of Shadows. For example, they might find that they can both enter the TV world and have to team up to face a powerful Shadow that is causing chaos in Inaba.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). There are often tags related to 'Persona 4', 'Yu', and 'Yukiko' which can help you narrow down the search. Another option is FanFiction.net, though the quality may vary more there. You can also check out some Persona - related forums where fans might share their favorite fanfics.
Maybe Yukiko is from a far - off land and comes to Konoha seeking help. Naruto, being the hero he is, steps forward to assist her. Along the journey, Naruto discovers that Yukiko has a connection to an ancient prophecy that he is also a part of. They then have to work together to figure out how to fulfill the prophecy, all while dealing with the politics and power struggles within the ninja villages.
Maybe the Velvet Room attendants from both games somehow get their worlds mixed up. Igor from Persona 5 and Margaret from Persona 4 have to work together to set things right. This leads to the characters from both games interacting. The Phantom Thieves might learn some new combat techniques from the Investigation Team and vice versa. They could then use these new skills to face a common threat that emerges from the merging of their two realities.