The ending of Twin Star Exorcists manga is quite complex and involves a final confrontation between the main characters and the ultimate evil. It leaves some room for interpretation.
One idea could be exploring the backstories of minor characters in more depth. For example, you could write about the childhood of one of the exorcist trainees and how they discovered their powers. Another idea is to create an alternate universe where the main characters have different personalities or roles. Maybe in this AU, Rokuro is a powerful demon instead of an exorcist.
One common theme is the clash of different power systems. For example, when Twin Star Exorcists crosses over with Naruto, the exorcist powers and ninja jutsus create an interesting contrast. Another theme is the adaptation of characters to new worlds. In a crossover with One Piece, the Twin Star Exorcists characters have to adapt to the pirate - filled world.
One interesting Twin Star Exorcists fanfiction could be about an alternate universe where the main characters have different powers. For example, Rokuro might have the power to control time instead of his usual exorcist abilities. This would change the whole dynamic of the story and the way he interacts with Benio.
One interesting part is the character interactions. The characters from Twin Star Exorcists, with their serious exorcist duties, meeting the friendly and often comical ponies of MLP can lead to some really fun and unexpected moments. Also, the way fanfic writers can blend the magic systems of both can be very engaging. For example, how the magic of friendship in MLP might affect the exorcism powers in Twin Star Exorcists.
Another option is to check out Tumblr. There are often fanfiction recommendations and some users even post their own short fanfictions or links to longer ones. It's a great place to interact with other fans of Twin Star Exorcists and discover new fan - made content.
One great Twin Star Exorcists crossover fanfiction is 'Twin Star Exorcists and Naruto: The Convergence'. It combines the unique exorcist world of Twin Star Exorcists with the ninja world of Naruto in an interesting way. The characters from both series interact in a way that feels natural given their personalities. Another one could be 'Twin Star Exorcists meets Bleach: Soul Bonds'. Here, the exorcist powers blend with the concept of souls in Bleach.
Sure. You can start by looking on platforms like FanFiction.net or Archive of Our Own. There are often stories that blend the unique elements of Twin Star Exorcists and My Little Pony in interesting ways. For example, some might have the exorcist characters enter the colorful world of Equestria in MLP, leading to all sorts of adventures and interactions between the two very different universes.