Mikey might be a character created to tell a story about Pop Rocks. He could be a fictional child used to illustrate the appeal or novelty of these candies. For example, he could be a curious and adventurous little boy who wasn't afraid to try new things, like Pop Rocks, which were quite different from other candies at the time.
In many fanfictions, Mikey is the optimist. He looks at the world with a positive outlook and tries to find the good in Rahzar. His friendly nature makes it easier for him to approach Rahzar, even though Rahzar might seem intimidating at first. Rahzar is usually depicted as having a lot of strength and power. He's a force to be reckoned with, but his character can also be complex, with hidden emotions that Mikey helps him uncover.
The abuse could be resolved if Mikey discovers a new power or ability within himself. This newfound strength gives him the confidence to face his abuser and put an end to it. Additionally, the support of other characters in the TMNT universe, like April or Splinter, could play a crucial role. They could offer advice, protection, or just be there for Mikey when he needs it most. Maybe they could even help Mikey expose the abuser to the authorities in the world of the story, if applicable.
April and Casey might also be part of this fanfiction. April could use her reporting skills to try and figure out what's going on with Mikey's mutation, and Casey would be ready to fight any new threats that come along because of Mikey's changed state. Also, Splinter, as their sensei, would be guiding them all through this difficult time, providing wisdom and training to help Mikey control his new powers if he has any.
For Mikey, you can focus on his positive traits like his bravery. Show him facing his fears when he's with Mouth. For example, if there's a spooky cave they need to enter, Mikey takes the lead even though he's scared.
Often in fanfiction, the love is shown through small, tender moments. Like when Christopher gives Mikey a special look or a gentle touch on the shoulder after a tough battle. These little gestures can speak volumes about his feelings. Also, he might always be by Mikey's side, supporting him in his decisions regarding Digimon and their journey.
Research the kappa mikey universe thoroughly. Know the settings, the other characters, and the overall tone. This will help you place your OC in the story in a believable way. Also, plan out a good plot. It could be a simple adventure or something more complex like solving a mystery.
They could develop their relationship through shared adventures. For example, when they go on a quest to find a lost artifact. During the journey, they face many difficulties. Mikey makes Shinigami laugh with his silly jokes in tough situations, and Shinigami protects Mikey when he gets in over his head. This way, their friendship deepens into a more trusting and closer relationship.