Regarding the situation with OU characters and their gender identity - it's really something that would depend from character-to-character and it's not something we can put a steadfast ruling to, as there's many canons where they dance around admitting a character isn't cisgender instead of outright saying it. So if a player wished to have their OU character be considered non-binary or trans - we wouldn't necessarily say no or make them be an AU unless it clearly contradicts canon (aka in cases where the character has been confirmed as cis).

However, we do ask that players going this route to carefully consider their intentions with doing such a headcanon. We have many non-binary and trans players in the game and we want them to feel like this is a game where their identities are respected. Ergo, there is an expectation that players doing such a headcanon are doing it in a respectful manner towards those communities.

That said, it should be noted that at this time OU player slots (which means any character that comes from another world than Kaisou's Earth, regardless of if they are OUs or AUs) are currently full. You are still welcome to app an Kaisou-based AU! Kaisou-based AUs are also allowed to be flexible with gender identities because they are AUs (though again, we still ask for respectful depictions).

Hope this clarifies things!