hi anon! thank you for liking my works and i'm flattered that you would ask me for help with your characterization!

writing can be difficult and intimidating at times, but i promise you there is no other feeling that comes close to how fulfilled you'll be when you're able to finish a fic! so this is me telling you not to feel scared about wanting to write and share your works! especially in a community like seokgyu that's always so ready to read a brand new fic lmao

as for your concern, mischaracterization is something that tends to happen either from a lack of source material or regard of it. in most cases what i think we tend to label as mischaracterization is the lack of plausibility when a character will say/do/think/feel something in the story cause we (the readers) personality believe they wouldn't. so when you're writing about a character it's always important to keep at least a few core factors about their personality or character trait as you're writing them.

you can pretty much write whatever kind of au you want, whether it's far from the canon setting or just a slight diversion, what's really important is making sure that the way your characters react to the world you put them in is believable. say for example, if you were to write seokgyu in a zombie apocalypse au, one key factor in their personality that you always need to remember is that these two are the biggest scaredy cats in the group. so in a au set where the literal undead is going to eat your brains at any given moment, their fear of scary things is something you need to keep in mind and make visible throughout the story, or if you want to take that personality away and keep it hidden, give your readers a reason to believe why they aren't scared or why they've overcome that fear. a good way to resolve that is their protective nature and their resilience. so make them have a goal in mind or someone to protect that would keep their minds focused on it rather than their fears.

basically what i'm trying to say is that you can pretty make them do all the things you want them to do in order for the plot to progress in your story, so long as it's in a way the character is able to react. obviously we don't really know the inner mechanisms of gyky's minds but we have plenty of content to use as basis, so we're not writing our stories blindly lmao

anyway, i'm not really sure if i'm making sense with this but i hope i was able to help you out (even if just a little bit) if you need any further help or if you want someone to talk to about your au, feel free to drop by anon!