Who could be the antagonist in 'Marcus and Dom meet in afterlife fanfiction'?

Well, it could be that they meet and reflect on their past lives. Maybe they realize the mistakes they made while alive and try to find a way to make amends in the afterlife.

Marcus and Dom could be two friends who had a very eventful relationship during their lives. Maybe they were soldiers together, or they grew up in the same neighborhood and had many adventures.

One possible plot could be that Marcus and Dom meet in an afterlife realm. Maybe they have unresolved issues from their lives and must face them together. They could relive certain memories, both good and bad, and through that process, find a sense of peace or redemption.

It could be Dr. Eggman. Maybe he has sent some of his robots to the area where Sonic and Tails first meet. The robots are causing chaos and Sonic and Tails have to team up to stop them, which is how they start to bond.

It could be a bully at their school. This bully might be a bigger animal, like a buffalo or a rhino, who picks on Nick because he's a fox. The bully might also tease Judy for being a small bunny with big dreams. Nick and Judy would have to team up to stand up to this bully, which would strengthen their bond.

Another possible antagonist could be a powerful vampire hunter. He sees Damon as a threat and Elena as a potential target or a way to get to Damon. When Damon and Elena meet, this hunter is already watching them. He plans to use their new relationship against them, making their first meeting the start of a lot of trouble for both of them.

Maybe a time - traveling villain from a different dimension who sees Lewis' sister as a threat to his plans of ruling all timelines. He constantly tries to thwart her efforts to make the future a better place. For instance, he might try to disrupt her attempts to introduce new technologies to the Robinson family that could benefit everyone. He would set up various traps and obstacles for her throughout her adventures in different time periods.

One possibility is that in the afterlife, Snape finally finds peace. He no longer has to hide his true loyalties or endure the scorn of those who misjudged him. He might be reunited with Lily, and they could have the conversations they never had in life. He could also meet with Dumbledore again, and they could discuss all the secrets and sacrifices that were made during the war.

It could be developed by exploring their past. Maybe they start to talk about their childhood memories that they haven't shared before. This kind of deep conversation can make them understand each other better and bring them closer. Another way is through facing a common enemy. They have to protect each other and in the process, their feelings for each other grow stronger. They learn to trust each other more and become more than just friends or partners, but truly soulmates.

There could be an ancient evil entity that has been awakened by Godzilla's presence. This entity wants to destroy everything in its path and sees Godzilla and Izuku as obstacles. It has the power to corrupt other creatures and turn them against our heroes, making it a very formidable antagonist.