In a fanfic about Optimus Prime x Megatron, their relationship could be explored in a more philosophical way. For example, they might debate the nature of good and evil, power and responsibility. Optimus believes in protecting all life, while Megatron has his own ideas about power and how it should be used. This kind of fanfic could show how their different viewpoints could either bring them closer together or drive them further apart.
In a Megatron x Optimus Prime fanfic, the story could also be about a power struggle within themselves. Megatron is tempted by an ancient power source that could give him ultimate control. Optimus Prime tries to stop him not as an enemy but as a friend who is worried about Megatron's well - being. Their interactions are filled with emotional turmoil as they try to balance their friendship with their duties.
A fanfiction could also explore a post - apocalyptic Cybertron where Megatron and Optimus Prime are the last two Transformers alive. They have to put aside their differences to try and rebuild their world. This would be a very emotional and character - driven story. They would have to confront their past actions and the reasons for their long - standing feud. As they work together, they might discover that they are not so different after all, and that their shared love for Cybertron could be the key to its restoration.
A great angle for a Megatron x Optimus Prime fanfic could be a body - swap situation. They are forced to inhabit each other's bodies due to some alien technology gone wrong. This leads to them having to understand each other's perspectives on a whole new level. They start to see the reasons behind their actions in the past and develop a new - found respect for one another.
The plot could be about a power struggle. Megatron wants total control over Cybertron, but Optimus Prime stands in his way. However, instead of just fighting, there are political intrigues involved. There could be other characters influencing their decisions. Maybe some Autobots who think Optimus is being too soft on Megatron, and some Decepticons who think Megatron is being too cautious.
In a fanfiction, it could be interesting to see a scenario where Megatron and Optimus Prime are reborn in a different time and place, perhaps in a peaceful Cybertron that has long forgotten the war. They might struggle to adapt to this new world where their old identities as war leaders are no longer relevant. Their journey could involve rediscovering themselves and learning to live in harmony, which would be a huge departure from their traditional roles.
Fanfiction about them can explore different universes and scenarios. For example, what if they were raised together? How would their relationship be different? It gives fans a chance to play with the established lore and create new and exciting stories that the official Transformers storylines may not explore. It also allows for deeper exploration of their motives and personalities.
One great Optimus Prime and Arcee fanfiction could be about them teaming up on a dangerous mission. They might face a new, powerful enemy that forces them to rely on each other's unique skills. Arcee's speed and agility combined with Optimus Prime's strength and leadership could make for an exciting story.
You can try looking on some fanfiction websites like Archive of Our Own (AO3). It has a large collection of Transformers fanfictions, and there might be some related to Optimus Prime and Megatron in the MPreg genre.
One possible fanfiction could be about Optimus Prime and Megatron having to team up against a greater threat. Maybe an ancient evil from Cybertron's past resurfaces that is so powerful that their usual enmity has to be put aside. They start off distrusting each other but as they face battles together, they gradually come to respect the other's fighting skills.
It could be developed by exploring their past. Maybe there was an event in their youth that they both remember differently. As they start to talk about it in the fanfic, they begin to see each other in a new light. For instance, they might have once been friends or at least comrades in a fight against a common enemy before their ideologies split them apart. This exploration of the past can build a more complex relationship between them.