A common theme is the clash of two different worlds. Sonic comes from a world full of natural landscapes and speed, while Megaman is in a world of technology and robots.
One idea could be a crossover with Sonic. Imagine Megaman and Sonic teaming up to stop a new villain who is causing chaos in both their worlds. They could combine their unique abilities, like Megaman's weapon switching and Sonic's super speed.
The popularity of Megaman Exe crossover fanfic lies in the fact that it allows fans to see their favorite characters in new and unexpected situations. It combines different universes and concepts, which is always exciting.
One idea could be to cross Megaman Zero with another popular game series like Sonic. Imagine Zero running at high speeds through the colorful zones in Sonic's world. Another idea is to cross him with a Final Fantasy world. Zero could be a mysterious warrior in that RPG setting, using his skills to fight against the powerful summons and magic - users there. Also, a crossover with the Metroid series would be cool. Zero exploring the desolate planets and facing off against the space - pirates and Metroids could make for an exciting fanfic.
A 'megaman x crossover fanfic' could involve a crossover with the Pokemon universe. X could end up in the Pokemon world and have to work with a trainer and their Pokemon to stop an evil organization that is using technology to harm Pokemon. He could use his weaponry to help in battles against the organization's powerful machines.
Sure. 'A Digital Union' is a great one. It combines different elements from the Megaman Exe universe in a really interesting way. The characters interact in new and exciting scenarios that fans of the series will surely enjoy.
First, decide which universe you want to cross Megaman Zero with. Then, research about that universe's lore, characters, and settings. For example, if it's a crossover with the Star Wars universe, learn about the Force, the different planets, and the various species. Next, think of a plot that can bring Zero into this new universe in a believable way. Maybe he gets transported there through a portal or is sent on a mission. Start with an interesting opening scene that grabs the reader's attention, like Zero waking up in a strange new world.
Develop an original plot. Instead of the typical 'stop the bad guy' plot, have the crossover be about something different. Say, a competition between the two universes where Megaman and the other crossover character have to prove which world has the better heroes. This will draw readers in as it's not the usual storyline.
Zero would be an obvious and interesting character to include. His backstory and his relationship with X could add depth to the fanfic. Also, in a crossover, he could have some unique interactions with characters from other franchises.
Well, you can start by looking on fanfiction.net. There are often some great Sonic and Megaman crossover fics there. Some might focus on the characters teaming up to fight a common enemy, like Dr. Eggman and Dr. Wily joining forces, and Sonic and Megaman having to use their unique abilities to stop them.