One interesting storyline could be the Necron Lord OC's struggle to regain their former glory in a universe that has changed much since their slumber. They might have to face new and powerful enemies while also trying to unite the disparate Necron factions under their rule.
Another storyline could involve the Necron Lord OC forming an unlikely alliance. For example, with a group of space marines. This alliance could be born out of mutual need, like facing a greater threat that neither can handle alone. The Necron Lord OC would have to navigate the cultural differences and suspicions on both sides, which could lead to some tense and interesting interactions.
One idea could be an Necron Overlord who rebels against the Silent King's plan. He might start to form alliances with other races in secret to gain power and knowledge. This could lead to a whole new set of power dynamics in the Warhammer universe.
The appearance and customization of Necron OCs can be really cool in fanfiction. They could have different color schemes or unique body modifications compared to the standard Necrons. For instance, an OC might have a more organic - looking part on their body as a remnant of their pre - Necron existence. Their personality also matters. A Necron OC could be more curious about the galaxy than the typical emotionless Necrons, leading them to explore places and engage in situations that normal Necrons wouldn't.
In some fanfictions, Eldar characters might be paired with a Necron Lord OC. This creates an interesting dynamic as the Eldar are a very different and ancient race. They could be either enemies, with the Necron Lord OC seeing the Eldar as a threat to their plans, or they could form a tenuous alliance based on a shared goal, like stopping a Chaos incursion.
In some persona 4 oc fanfiction, an OC might be a detective who is secretly investigating the strange happenings in Inaba. This OC could have their own set of skills and resources, and as they dig deeper, they discover connections between the real world and the TV world that the main characters haven't noticed yet. Their investigations could also put them in danger and lead to some intense action scenes.
Another could be an OC with the Omnitrix getting stuck in a parallel universe where the rules of the Omnitrix are different. For example, instead of being able to transform into known aliens, the OC has to figure out how to use new and strange alien forms that are native to that universe. This could lead to all sorts of adventures as the OC tries to find a way back home.
Another could be a love story within the context of the royals. An original character might fall in love with a royal heir. There could be many obstacles such as differences in social status and the expectations of the royal family. But their love overcomes all these difficulties in the end.
One interesting storyline could be about an original character (OC) who is a half - elf with unique magic abilities trying to find their place in the war - torn world of Warcraft. They might struggle between the two sides of their heritage.
A really engaging storyline might be the OC having to train a young rookie. They take this newbie under their wing, but the rookie has some bad habits that the OC has to break. It's a story of mentorship, growth, and the clash of different generations in the WWE world.
One interesting storyline could be an OC (original character) who is a spy behind enemy lines. They have to use their wits and unique skills to gather intelligence without getting caught.
One interesting storyline could be the nanny getting involved in a local community event in the OC. Maybe she helps organize a charity fundraiser and in the process, she forms new friendships and overcomes some personal insecurities. Another could be her relationship with the family she works for evolving in unexpected ways, like she starts teaching the kids some unique skills that the parents are really impressed by.