One idea could be an OC who is a long - lost relative of Aquaman. They could have unique powers related to water control but in a different way than Aquaman. For example, the OC can turn water into different shapes and use them as weapons. Another plot could involve the OC being from a hidden underwater tribe that has a different view on Atlantis's rule. The OC could try to bridge the gap between their tribe and Atlantis while also joining the Justice League to fight common threats.
An interesting plot could be that the OC is a human who has an accident and gains the ability to communicate with sea creatures like Aquaman. They then get caught in the middle of a power struggle in the underwater world. Maybe there's a new villain who wants to take over Atlantis and the OC, with their newfound abilities and their knowledge of the surface world, has to help Aquaman and the Justice League stop the villain. They could also struggle with adapting to their new life as part of the underwater world and the superhero team.
One idea could be an OC with the power to manipulate time joining the Justice League. They could accidentally create alternate timelines while trying to stop a villain, and the Justice League has to fix it. For example, the OC might go back in time to prevent a major disaster but end up changing the course of events in a way that makes the villain even more powerful in the new timeline.
One idea could be an Immortal OC who has ancient knowledge and uses it to help the Justice League prevent a threat that was foretold in a long - lost prophecy. For example, this OC might know of a hidden weakness in an upcoming powerful villain.
Maybe the OC Kryptonian has a power that is malfunctioning. They struggle to control it and it causes problems within the Justice League at first. But through the help of other members like Superman, they learn to master it. This could lead to a story of self - discovery and friendship within the team. They could face a villain who specifically targets their power, making it a race against time to get it under control.
One idea could be that the OC has a unique power that the Justice League initially distrusts but later comes to rely on. For example, the OC can manipulate time in small bursts, which at first seems dangerous but is actually crucial in stopping a villain who can freeze time.
One idea could be an OC who is a long - lost relative of Aquaman. They have a unique power that helps in a crisis in Atlantis. For example, they can communicate with a special species of sea creatures that no one else can, and this ability becomes crucial in stopping an ancient evil from rising.
One idea could be an OC with the power to manipulate time joining the Justice League. They could accidentally create a time rift during a battle, and the League has to fix it while also dealing with the OC's insecurities about their powers.
One idea could be an OC God who has the power to manipulate time. This God could be a new threat to the Justice League as they struggle to understand and combat this power. For example, the God could reverse important events in the League's history, causing chaos.
One idea could be a crossover where the Young Justice team has to team up with the Justice League to face an interdimensional threat. Maybe a powerful villain from another dimension is trying to invade Earth and the combined skills and powers of both groups are needed to stop it.
Maybe a story where some of the younger members of the Young Justice team are frustrated with the Justice League's methods and decide to take on a mission on their own, but end up getting in over their heads and have to call in the League for help. This could lead to a lot of character development and some interesting dynamics between the two groups.
One idea could be an oc who is an old god's descendant and tries to join the Justice League. They might have unique powers that both amaze and worry the League members.