Another idea is that OC has a special ability that Elizabeth discovers can help them control the Big Daddies in a different way. They then use this to their advantage to take on the main antagonists in Rapture, like Sofia Lamb. As they do this, a bond forms between them, and they learn more about each other's pasts and how they ended up in this strange and terrifying place.
Perhaps OC is from the surface world and comes to rescue Elizabeth. Along the way, they have to face the moral dilemmas of the underwater city, like whether to use the power of ADAM or not. This would create a lot of tension and character development as they journey through the dangerous and beautiful but corrupt world of Bioshock.
One idea could be that the OC is a protector of the Little Sisters. He or she tries to shield them from the dangers of Rapture while also trying to understand their unique bond with the Big Daddies. Maybe the OC discovers a way to break the cycle of the Little Sisters' harvesting without harming them.
One idea could be exploring the backstory of a minor character in the Bioshock universe. For example, a splicer's journey before they became spliced. It could show how they were once an ordinary citizen of Rapture and what led them to make the fateful decision to use ADAM. Another plot could focus on an alternate timeline where the protagonist makes different choices. Maybe they side with the wrong faction and have to deal with the consequences. A third idea is a story centered around a new type of plasmid that has unexpected effects on the user and how it impacts the power dynamics in Rapture.
OC could be developed by giving them a unique backstory related to the world of Bioshock. For example, they could be a descendant of an early Rapture scientist who was sent away before the fall. This would give them a connection to the place and a reason to explore it.
One interesting story could be about an original character who has unique powers and how they navigate the complex world of Bioshock Infinite. Maybe they have the ability to control the Songbird in a different way than the main characters in the game.
One idea could be that Big Brother is a protector in the BioShock world, guiding Little Sister through the dangerous and strange underwater city. He helps her avoid the Splicers and find the ADAM she needs in a more ethical way, like by using his combat skills to take out the Big Daddies first so she can harvest safely.
One idea could be a crossover with another game like "The Elder Scrolls". Imagine Booker DeWitt finding himself in the world of Skyrim. He could use his skills and weapons from BioShock Infinite in a completely different fantasy setting, facing off against dragons and magic - using vigors in a new and unexpected way. Another idea might be a crossover with a science - fiction series like "Mass Effect". How would the plasmids and the genetic manipulation in BioShock Infinite interact with the biotics and advanced technology in Mass Effect? It could lead to some really cool battles and character interactions. Also, a crossover with "Alice in Wonderland" could be fascinating. Picture Elizabeth falling down the rabbit hole into Wonderland. Her ability to open tears could have a really interesting impact on the strange and dream - like world of Wonderland, perhaps creating new areas or changing the rules of the land.
Well, it could be that the baby falls ill and this causes a great deal of worry and stress for Mr Darcy and Elizabeth. During this difficult time, they rely on their love for each other and their child to get through. It also shows how they both grow as parents, with Elizabeth being the more nurturing presence and Mr Darcy using his resources and influence to get the best medical help available.
One idea could be that Merlin and Elizabeth go back in time to Camelot's golden age. They could use their modern knowledge to solve ancient problems. For example, they might introduce new medical techniques that save lives. Another plot could involve them trying to prevent a major disaster in Camelot's past that they know about from history books. They might also have to deal with the cultural shock of living in a different time period.
One plot idea could be that after the kiss, they face opposition from their families. Darcy's family might think Elizabeth is not of a high enough social standing, while Elizabeth's family could have misunderstandings about Darcy's intentions. Another idea is that the kiss is a spur - of - the - moment thing during an argument, and then they have to deal with the emotional fallout and realization of their feelings. Maybe they are in a public place when they kiss, and it causes a scandal in their society, forcing them to either confront or hide their relationship.
One idea could be to explore their courtship in more detail. Maybe show Elizabeth's initial hesitations and how Edward overcame them. Another could be a story set during a time of political unrest, and how their relationship was affected by it. For example, they might have to make difficult decisions to protect each other and their family.